81 



iiilliiB^^^^^^^ 



l^iii!: 






TX749 



LIBRARY OF CONGRESS 




DDD027T33Ta 



1018 Issued October 18, 1907. 

U. S. DEPARTMENT OF AGRICULTURE. 

OFFICE OF EXPERIMENT STATIONS— BULLETIN 193. 

A. C. TRUE, Director. 



STUDIES OF THE EFFECT OF ft 
DIFFERENT METHODS OF COOKING 
UPON THE THOROUGHNESS AND EASE 
OF DIGESTION OF MEAT 

AT THE UNIVERSITY 
OF ILLINOIS. 




BY 

H^SfGRINDLEY, D. Sc, 

I, 

Professor of General Chemistry, College of Science, Universitij of Illinois, 

WITH THE COOPERATION OF 

TIMOTHY MOJONNIER, M.S., 

AND 

HORACE C. PORTER, Ph. D. 




WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 
190T. 



a/ 



U^^ 






THE OFFICE OF EXPERIMENT STATIONS. 

STAFF. 

A. r. Tiu E, D. Sf., Director. 

E. W. Allen, Ph. D., Assistant Director and Editor of Experiment Station Bccord 

W. H. Beal, B. a., i\I. E., Chiif of Editorial Division. 

C. F. Lan'gwokthy, Ph. D., Chiif of Xutrition Invcstiaations. 

R. D. MiLNEii, Ph. D.. Assistant in Nutrition Investigations. 

(2) • . 



WIAR31 19:3 
D. ot 0. 



LETTER OE TRANSMITTAL. 



U. S. Department of Agriculture, 

Office of Experiment Stations, 

WasMngton, D. C, June 20, 1907. 

Sir: I have the honor to transmit herewith and recommend for 
publication as Bulletin 193 of this Office, a report of investigations 
on the digestibility and nutritive value of meat, conducted by H. S. 
Grindley, professor of general chemistry in the college of science of 
the University of Illinois, Timothy Mojonnier, and Horace C. Porter, 
as a part of the cooperative nutrition investigations of this Office. 
The report includes the results of 67 natural and 99 artificial diges- 
tion experiments with meat, undertaken to determine the ease and 
thoroughness of digestion of different Idnds and cuts of meats cooked 
in a variety of ways. These studies form a part of the investigations 
which have been in progress at the University of Illinois from 1898 
to 1907 to determine the effects of cooking upon the nutritive value 
of meat. 

The results reported are of widespread interest, as they show that 
meat of all sorts is to be classed among the very digestible foods, and 
that differences in kind, cut, or method of preparation for the table 
have less effect upon the ease or the thoroughness of digestion than has 
been frequently claimed. 

The editorial work in preparing the reports of these investigations 
for publication was done by R. D. Milner of this Office. 

Respectfidly, A. C. True, 

* Director. 

Hon. James Wilson, 

Secretary of Agriculture. 

(3) 



CONTENTS, 



Page. 

Introduction 5 

Experiments on the thoroughness of digestion of meats 5 

Work of other investigators 6 

Investigations here reported 6 

Experimental methods 7 

Comjx isit inn of food materials 7 

Composition of feces 10 

Details of experiments with mixed diet, including meat 12 

Experiments with amounts of food not restricted 12 

Experiments with definite amounts of food and of uniform muscular 

exercise 15 

Experiments with \arying amounts of food and of muscular exercise. . 19 

Details of experiments with simple diet, including meat 24 

Experiments with lean beef cooked in water for 1 hour 27 

Experiments with lean beef cooked in water ior 2 hours 28 

Experiments with lean beef cooked in water for 3 hours 30 

Experiments with lean beef pan broiled 31 

Experiments with lean beef fried 32 

Experiments with lean beef roasted 32 

Experiments with fat beef cooked in water for 2 hours 33 

Experiments with beef ril:)s roasted 34 

Experiments with fat veal leg roasted 36 

ExperimtMits with mutton leg roasted 38 

Experiments with pork roasted 39 

Summary and discussion of results 40 

Digestibility of the nitrogen (protein) as corrected for metaliolic products in 

the feces -17 

Income and outgo of nitrogen and gain or loss of protein 52 

Investigations on the ease or rapidity of digestion of meat 59 

Examination of stomach contents 59 

Artificial digestion experiments 61 

Investigations here reported 63 

Development of method '. 64 

Tests of method adopted 72 

Details of experiments on the ease of digestion of protein 76 

Experiments with beef 78 

Experiments with mutton 89 

Experiments with pork 90 

Summary and discussion of results '. 94 

Conclusions - 99 

(4) 



EFFECT OF COOKING UPON DIGESTION OF MEAT 



INTRODUCTION. 

Ill connection with the nutrition investigations of the Department 
of Agricuhure studies have been made at the University of Ilhnois, 
in cooperation with the Office of Experiment Stations, of the various 
factors which affect the nutritive vahie of meats. A part of this 
inquiry has been discussed in previous bulletins" of this Office, 
wliich report studies of the changes in the nature and propor- 
tions of the nutritive ingredients of the meat that are produced by 
cooking. ^Another part of the research is taken up in the present 
bulletin, which reports investigations on the effect of cooking upon 
the digestibility of the meat. Two Imes of work have been followed 
in these investigations. The more important concerns the thorough- 
ness with wliich different kinds and cuts of meats, cooked in different 
ways, may be digested by man in normal health — that is, the propor- 
tions of the nutrients of the meats that would be actually dissolved 
and absorbed during their passage through the alimentary canal. In 
addition to this, however, an attempt was made by means of artificial 
digest^'on experiments to gain some knowledge regarding the eft'ect of 
cooking in general, and different methods of cooking in particular, 
upon the ease or rapidity of the peptic digestion of the proteid of the 
meat. 

EXPERIMENTS ON THE THOROUGHNESS OF DIGESTION OF MEATS. 

The thoroughness with which a given food material may be digested 
can be studied satisfactorily only by means of natural digestion 
experiments in which the quantities of nutrients in the material 
eaten are determined and compared with those in the feces excreted. 
Such experiments are sometimes made with dogs and other animals, 
but the most satisfactory are those made with men. Only those 
made with men are here considered. 

oU. S. Dept. Agr., Office of Experiment Stations Buls. 102, 141, 162. 

(5) 



WORK OF OTHER INVESTIGATORS. 

A number of investigators have studied the thorouglmess of diges- 
tion of cooked meat. For example, Hofmami" compared the diges- 
tibihty of meat protein with that of vegetable foods. Rubner* 
studied the digestibility of roasted lean beef in connection with an 
extended study of the digestibility of single food materials. Atwater'^ 
studied the comparative digestibility of beef and fish, in an investiga- 
tion on the nutritive value of these two kinds of animal food. An 
experiment was made by Malfatti'' with roasted and boiled beef. 
Solntzev^ made experiments with canned beef and mutton and with 
similar meats freshly prepared and cooked in water at 85° C. ; and 
Smetski ' studied the asshnilation of the nitrogenous constituents of 
boiled salt meat. Solomin ^ investigated the digestibility of tripe. 
No attempt has been made to include here a complete summary of 
the work of this nature, for the reason that in general the results of 
experiments such as these do not throw much light on the c[uestion 
as to what effect different methods of cooking have upon the digesti- 
bility of the meat. C. Forster,'' however, has published the results 
of an extended studv of the digestibilitv of dift'erent cuts of beef 
cooked in different ways as compared with that of raw beef. These 
are considered in some detail on page 45, in a comparison with the 
results obtained in the investigations reported in the present bulletin. 

INVESTIGATIONS HERE REPORTED. 

In the present bulletin the results of 67 digestion experiments with 
men are given. These experiments were of two kinds. In 23 of 
them the meat was eaten in a rather varied ration, the purpose being 
to determine the effect of different methods of cooking meat upon 
the digestibility of an ordinary mixed diet, including meat, beef being 
the meat selected. In the remaining 44 experiments the meat was 
eaten in a very simple diet, the food materials other than meat 
being those the digestibility of which is fairly well established, so 
that by making due allowance for these the digestibility of the meat 
itself may be calculated. Of these, 31 experiments were ^^^th beef 
cooked in water for different lengths of time, and by roasting, trying, 

a Reported by Yoit in Sitzber. K. Bayer. Akad. Wiss. Math. Phys. Kl., 1869, Pt. 2, 
p. 483. 

ftZtschr. Biol., 15 (1879), pp. 121-125. 

cZtschr. Biol., 24 (1888), pp. 23-25. 

d Sitzber. K. Akad. Wiss. [Vienna]. Math. Xaturw. Kl.. 90 (1884), No. 3. p. 323. 

e Preserved Food for Armies. Inaug. Dis^., Univ. St. Petersb., 1886. pp. 94-98. 

/The Composition of Salt Meat and the Assimilation of its Nitrogenous Constituents. 
Inaug. Diss., Univ. St. Petersb., 1886. 

j/Arch. Hyg.. 27 (1896). p. 182. 

ADer Nahiwert des Ilindfleisches. Inaug. Diss., Univ. Berlin, 1897. 



and pan broiling; and 6 were mth veal, 3 with mutton, and 4 with 
pork, all roasted. The results of the experiments with beef show 
the effects of different methods of cooking upon the digestibility of 
the meat, and a comparison of the results with the various meats 
cooked in the same way shows the relative digestibility of different 
kinds of meat. 

In all the experiments with simple diet a study was made of the 
amounts of metabolic nitrogen in the feces, and in all the 67 experi- 
ments the urine was collected and the l)alance of income and outgo 
of nitrogen was determined. 

EXPERIMENTAL METHODS. 

The methods followed in these experiments were similar to those 
described in former bulletins of this Office; hence a brief statement 
wall suffice here. In general, the various food materialc were eaten 
ad libitum, the amount of each article eaten being recorded and a 
sample reserved for analysis. The feces for the total experimental 
period were collected and analyzed. The digestibility of the nutri- 
ents of the total diet was determined from the quantity of each in 
the food and in the feces. In the experiments with simple diets the 
digestibility of the nutrients of the meat alone was computed from 
the data for the total diet by allowing for the digestible nutrients of 
the materials eaten with the meat, as explained in the description 
of such experiments (p. 26). 

Aside from these general principles, however, the different groups 
of experiments recorded herein differed considerably in some details. 
Those details that pertain particularly to given experiments are 
therefore given in connection with the other data of the experiments. 
The different kinds of experiments included in the investigation are 
considered separately on the following pages. The data regarding 
composition of food material and feces for the natural digestion 
experiments are here tabulated. 

COMPOSITION OF FOOD MATERIALS. 

Samples of all the food materials used iri the experiments were 
analyzed according to the usual methods, with such minor modifica- 
tions as have been found expedient. Nitrogen was determined by 
the Kjeldahl method. Moisture was determined by heating the sam- 
ple for sixteen hours at 104° C. in a current of hydrogen. Ether 
extraction by the Soxhlet method was continued for twenty-four 
hours in the case of meat and baked beans, for sixteen to twenty 
hours in the case of bread, breakfast food, and bananas, and for 
about twelve hours in the case of milk. The results of the analyses 
are given in Table 1. 



8 

Table 1. — Composition of food materials in natural digestion experiments here recorded. 



Lab- 
ora- 
tory 
No. 


Food material. 


Used in 

experiment 

No. - 


Water. 


Protein 
(NX6.25). 


Fat. 


Carbo- 
hy- 
drates. 


Ash. 








Per ct. 


Per ct. 


Per ct. 


Per ct. 


Per ct. 


610 


Beef, round, pan broiled 


267-270 


66.59 


26.08 


3.14 




3.82 


613 


do 


267-270 


66.60 


26.31 


3.04 




3.87 


716 


Beef, round, cooked in water 2 hours. . 


271,272 


61. 86 


29.07 


6.10 




3.46 


718 


do 


271,272 


61.64 


28.98 


6.07 




3.30 


739 


Beef, round, cooked in water 4 hours . . 


273,274 


63. 92 


25.97 


7.52 




2.73 


740 


do 


273, 274 
275 


63. 77 
56.98 


26.15 
35.71 


7.56 
4.97 




2.74 


783 


Beef, round, cooked in water 2 hours . . 


2.01 


798 


do 


276 


54.68 


35.09 


7.97 




1.82 


809 


.do 


277 
278 
279 
280 


53.73 
64.12 
64.83 
62.30 


36.13 

26.64 
26. 07 
28.64 


7.51 
6.74 
5.72 
6.86 




2.81 


825 


Beef, round, fried in butter 


2.28 


839 


do 


1.58 


849 


Beef, round, cooked in water 20 minutes . 


1.67 


861 


do 


281 
282 
283 
284 
285 
286 
287 
288 
289 
291 
293.294 
295, 296 


60.71 
66.39 
62.96 
56.95 
55.99 
56.12 
56.97 
58.96 
57.87 
62. 10 
67. 59 
56.72 


32.-61 
23.24 
27.97 
31.52 
31.64 
33.84 
34.37 
32.18 
35.06 
30.16 
26. 29 
34.35 


5.25 
8.43 
7.18 
9.33 
9.77 
8.13 
6.08 
6.53 
5.54 
5.75 
3.91 
7.11 





1.61 


871 


Beef, round, roasted 


1.31 


884 


.. ..do 


1.45 


899 


Beef, round, cooked in water. 


2.16 


925 


do . . . 


2.12 


963 


do 


1.82 


988 


. ..do 


3.40 


1029 


....do 


1.74 


1054 


do 


2.08 


1108 


do . 


2.15 


1131 


.do 


1.76 


114S 


do 


1.71 


1216 


do 


298. 299 


64.86 


30.76 


2.47 




1.62 


1244 


do 


297-300,301 


68.45 
60. ()7 


27.42 


2. ,34 




1.62 


1116 


do 


291 


33.80 


4.07 




2.21 


1107 


Beef, round, raw 


291 


75.20 


19.21 


4.76 




1.00 


1119 


do 


290-292 


74.41 


20. 84 


3.71 




1.05 


1130 


do... 


293, 294 


76. 54 


20.68 


1.97 




1.07 


1287 


Beef, shoulder, cooked in water 


368-370 


49.39 


22.61 


26.46 




1.60 


1313 


Beef, round, pan broiled 


371-373 


56. 98 


28.46 


12.24 




2.58 


133J 


Beef, round, : ried in lard ; . . . 


374-37ti 


52. 26 


33.97 


11.22 




2.58 


1347 


Beef, round, roasted 


377-379 


.59. 12 


29.77 


8.30 




3.20 


1525 


Beef, ribs, roasted 


422,423 


44.43 


20.08 


34.09 





1.93 


1561 


do 


426, 427 


55.11 


24.64 


18.21 




2.55 


1595 


do 


428 


49.88 


20.56 


28. 06 




2.37 


1617 


do 


429. 430 


43.51 


23.63 


30.67 




2.34 


1400 


Veal, leg, roasted 


380-382,383 


53.17 


28. 12 


16.56 




2.34 


1469 


do 


419.421 


66.20 


28.38 


3. 34' 


2. 47 


1438 


Mutton, leg, roasted 


381.384,385 


50. 58 


25. 10 


21.82 




2.89 


1447 


do.... 


381,384,385 


52.05 


29. 57 


17.05 




2.45 


1452 


Pork, fresh ham, roasted 


386, 387 


47.09 


31.82 


20. 04 




2.26 


1546 


do 


424 


53.02 


25. 13 


20.24 




2.37 


15(iO 


do 


425 


54.65 


26. 10 


16.27 




3.23 


620 


Butter 


267, 268 


8.67 


.46 


88.65 




2.22 


621 


do 


267,268 


8.83 


.70 


88.39 




2.08 


656 


do 


269,270 


8.55 


.49 


88.46 




2.50 


657 


. ..do 


269, 270 

271,272 

273,274 

275 

276 

277 

278 

279 

280 

281 

282 

283 

284,285 

286. 287 

288. 289 

290,292 

293, 294 

2f>5, 296 


7.75 

9.03 

8. 99 

10.50 

7.13 

12.32 

9.28 

9.01 

8.17 

9.31 

8.53 

6.42 

11.94 

12.45 

13. 37 

6.94 

6. 40 

9.46 


.48 
.52 
.56 
.69 
.80 
.40 
.38 
.54 
.60 
.56 
.64 
.81 
.55 
.52 
.56 
.81 
.6l' 
.60 


89.58 
88.42 
88.47 
86. 61 
90.74 
84.55 
88.29 
87.39 
89.03 
88.80 
89.75 
90.32 
82.05 
82.65 
81.07 

91. 70 

92. 64 
89.22 




2.19 


713 


do 


2.03 


741 


do 


1.98 


786 


.. .do 


2. 20 


802 


do . 


1.33 


813 


do.. 


2.73 


828 


.do 


2.05 


837 


do . . . 


3.06 


852 


do 


2.20 


864 


do 


1.33 


874 


.. ..do 


1.08 


885 


do 


2.45 


902 


Butter, creamery 


5.46 


964 


do 


4.38 


1032 


....do 


5.00 


1123 


do 


.55 


1133 


.do 


.34 


1150 


do 


.72 


1208 


do 


297-301 


11.42 


.66 


87.68 




.24 


1286 


do 


368 
.371,374 

377 
382,383 
384, 385 
.386,387 
420,421 
422, 423 
424. 425 
426, 427 

428 
429. 4,30 
267,268 


6.82 

8.75 

7.69 

13.61 

12.81 

11.72 

9. 83 

12. 73 

10. 11 

11.02 

8.62 

11.07 

86.92 


.(» 
.80 
.47 
.82 
.79 
.55 
. ,55 
.55 

1.00 
.70 
.67 
.82 

3.21 


89. 92 
88.09 
89. 45 
82.69 
83. 22 
85. 62 
88.00 
84.35 
87.80 
85.90 
88.33 
86.09 
4.34 




"i'so" 


2.66 


1312 


■ do 


2.36 


1345 


.do 


2.39 


1407 


Butter 


2.88 


1436 


do 


3.18 


1451 


.do 


2.11 


1468 


do 


1.62 


1526 


do . .: 


2.37 


1549 


do 


1.09 


1564 


. ..do 


2.38 


1598 


do 


2.38 


1620 


.do 


2.02 


622 


Milk 


.73 



Table 1. — Composition of food materials in natural digestion experiments here recorded- 

Continued. 



Lab- 
ora- 
tory 
No. 


Food material. 


Used in 

experiment 

No.- 


Water. 


Protein 

(NX6.25). 


Fat. 


Carbo- 
hy- 
drates. 


Ash. 


623 


Milk 


267, 268 

269, 270 

271,272 

273,274 

275 

276 

277 

278 

279 

280 

281 

282 

283 

284 

284,285 

286 

288 

285 

287 

289 

291 

295,296 

298, 299 

300 

29/, 300, 301 

368-370 

3ti9 

371-373 

374-376 

377-379 

380,382,383 

3S0,382.383 

381,384,385 

386,387 

419-421 

422.423 

424,425 

426.427 

428 

429, 430 

267,268 

267,268 

267,268 

269,270 

269, 270 

271,272 

271,272 

273.274 

273,274 

275 

276 

277 

278 

279 

280 

281 

282 

283 

284 

285 

286 

287 

288 

289 

290 

291,292 

293,294 

295,296 

297,298 

299-301 

368-370 

371-373 

374-376 

377-379 

380-383 

381,384,385 

386. 387 

417,420,421 


Per ct. 
86.92 
86.32 
87.11 
87.24 
86.62 
87.11 
88.37 
87.75 
87.59 
86.88 
86.90 
88.15 
87.72 
91.25 
92.37 
91.37 
91.41 
87.92 
87.92 
88.20 
89.18 
88.46 
88.60 
88.53 
87.64 
87.37 
89.33 
87.83 
87.46 
87.14 
86.00 
S7.69 
87.81 
87.67 
87.13 
86.02 
87.84 
87.30 
87.29 
87.44 

• 41.31 
37.78 
44 81 
39.02 
39.39 
39.37 
40.20 
38.80 
38.80 
44 19 
44 20 
44 37 
41.59 
42.55 
42.00 
41.42 
44 84 
42.53 
43.41 
44 17 
44 15 
45.04 
43. 52 
44 14 
45.58 
44 57 
44 66 
47.22 
43.92 
45.62 
44 24 
42.23 
44 95 
43.52 
44 11 
44 07 
43.08 
45.56 


Per ct. 
3.27 
3.35 
3.15 
3.25 
3.55 
3.46 
2.67 
2.78 
2.79 
2.77 
3.04 
2.48 
2.63 
3.13 
2.85 
3.10 
3.03 
3.37 
3.23 
3.08 
3.01 
2.75 
3.04 
2.83 
3.16 
2.74 
2.28 
2.70 
2.86 
2.89 
3.17 
3.04 
3.26 
3.18 
3.13 
3.25 
3.23 
3.00 
3.02 
2.99 
7.39 
7.77 
7.04 
8.09 
7.86 
7.92 
7.77 
7.98 
7.90 
7.39 
7.76 
7.53 
9.04 
8.40 
8.52 
8. 06 
8.30 
8.76 
8.26 
8.12 
8.3.1 
8.24 
8.76 
8.48 
7.47 
7.89 
■7.76 
7.28 
7.46 
7.20 
8.61 
9.34 
9.31 
9.41 
9.05 
9.08 
9.15 
8.01 


Per ct. 

4 37 

4 64 

4 11 

3.80 

4 33 

4 36 

3.37 

3.57 

4 21 

4 36 

4 74 

3.84 

3.83 

.39 

.42 

.19 

.10 

3.68 

3.76 

3.65 

2.94 

3. GO 

3.18 

3.37 

3.93 

4 17 

2. 79 

4 31 

4 25 

4 16 

5.35 

3.86 

3.69 

3.83 

4 41 

5.71 

3.87 

442 

4 16 

4 20 

3.01 

3.14 

2.70 

2.48 

2.47 

2.35 

2.42 

3.46 

3.34 

.89 

.48 

1.36 

1. 16 

1.11 

1.31 

.88 

.71 

.85 

.96 

.72 

.,56 

.46 

1.00 

.70 

.36 

.38 

.38 

.16 

.74 

.74 

.88 

.54 

.27 

.59 

.39 

.41 

.31 

.40 


Per ct. 

4 80 

4 94 

4 90 

4 99 

4 74 

4 31 

4 84 

• 5.16 

4 70 

5.27 

4 60 

4 86 

5.13 

4 49 

3.70 

4 62 

4 71 

4 29 

4 38 

4 33 

4 18 

4 52 

4 48 

4 61 

4 58 

5.04 

4 93 

450 

460 

5.06 

4 76 

4 74 

4 51 

4 49 

4 61 

4 37 

4 34 

4 58 

4 87 

4 69 

47.13 

50.10 

44 34 

49. 28 

49.25 

49.37 

48.62 

48.85 

49.04 

46.67 

46.27 

46.91 

47.46 

47.14 

47.42 

48.76 

45.49 

47.17 

46.57 

46.09 

45.91 

45.34 

4a 69 

4,5. 94 

45.24 

46.34 

46.51 

44 65 

47.05 

45.77 

45.39 

47.05 

44 64 

45.76 

45.59 

45.67 

46.75 

45.21 


Per ct. 
0.64 


670 


do 


.75 


723 


do. 


.73 


746 


....do 


.72 


789 


do 


.76 


an 


. . do 


.76 


812 


do 


.75 


829 


do 


.74 


838 


do . 


.71 


853 


. ..do 


.72 


865 


do 


.72 


875 


.do 


.69 


886 


do 


.69 


898 


Milk, skim 


.74 


927 


. do 


.66 


985 


do 


.72 


1031 


do 


.75 


928 


Milk , whole 


.74 


990 


do 


.71 


1057 


. do 


.74 


1117 


do 


.69 


1151 


.do 


.67 


1209 


. .do 


.70 


1232 


do 


.66 


1234 




.69 


1285 


.. ..do 


.68 


1301 
1311 
1329 
1346 
1405 


do 

do 

do 

do 

Milk 


.67 
.66 
.83 
.75 
.72 


1429 


do 


.67 


1435 


do 


.73 


1449 


do 


.83 


1466 
1523 


do 

.. .do 


.72 
.65 


1547 


do 


.72 


1562 


do . . . 


.70 


1597 


do 


.66 


1619 


do . 


.68 


614 


Bread. 


1.17 


616 


do 


1.21 


617 


do. . 


1.11 


652 


do 


1.13 


655 


do 


1.04 


710 


.do.. . . 


.99 


712 


do 


.99 


735 


do 


.91 


736 


. .do 


.91 


785 


do 


.86 


799 


do.. 


1.29 


810 


do 


.83 


826 


do 


.75 


840 


do 


.80 


850 


do 


.75 


862 


.do 


.88 


872 


do 


.66 


882 


do . . . 


.69 


901 




.80 


924 


do 


.89 


962 


do . . . 


1.00 


989 


....do 


.92 


1030 


do 


1.03 


1056 


. ..do 


.74 


1109 


do 


1.35 


1122 


.. .do.. .. 


.82 


1132 


do 


.69 


1149 


do . 


.89 


1207 


do 


.83 


1233 


do .... 


.67 


1284 




.88 


1327 


do ; 


.84 


1328 
1344 
1404 
1437 
1450 
1467 


do 

do 

Bread 

do 

do 

do 


.83 
.72 
.86 
.77 
.71 
.82 



10 

Table 1. — Composition of food materials in natural digestion experiments here recorded- 

Continued. 



Lab- 
ora- 
tory. 
No. 



1524 

1548 

1563 

15t){) 

161S 

60S 

787 

797 

897 

624 

625 

650 

651 

724 

747 

784 

800 

811 

827 

841 

851 

863 

873 

883 

900 

923 

961 

987 

1028 

1055 

626 

639 

627 

638 

669 

668 

722 

721 

744 

745 

926 

950 

986 

1026 

1053 

1088 

609 

609 

788 

896 



Food m.-itcrial. 



Bread 

do 

do 

do 

do 

Breakfast food 

do 

RoUed oats 

Creiuii of wheat 

Beans, Itaked 

do 

do 

do 

do 

do 

do 

do 

do 

do 

do 

do 

do 

do 

do 

Beans, canned baked. 

do 

do 

do 

do 

do 

Bananas 

do 

do 

do 

do 

do 

do ; 

do 

do 

do 

do 

....do 

....do 

....do 

do 

do 

Sugfl r 

do 

do 

do 



Used in 

experiment 

No. - 



Water. 



422.423 
424, 425 
426, 427 
428 
429.430 
207-274 

275 ; 

275-283 

284-289 

267,268 

267,268 

267-270 

267-270 

271,272 

273,274 ' 

275 i 

276 

277 ' 

278 

279 

280 

281 

282, 

283 

284 

285 

286 

287 

288 

289 

267 

267 

268 

268 

270 

269 

271 

272 

274 

273 

284 

285 

286 

287 

288 

289 

267-274 

280-283 

275-279 

284-289 



Per ct. 
43.57 
43.97 
43.27 
44.31 
41.99 

9.93 
11.88 

8.82 
12. 40 
67.42 
67.58 
67.46 
67.60 
68. 86 
69.44 
66.69 
66.07 
66.17 
66.03 
66.97 
67.34 

65. 61 

66. 22 
(16. 51 
70 25 
70.30 
69.68 
67.34 
67.07 
67. 06 
76. 71 
77.58 
76. 25 



Protein 
(NX6.25), 



Fat. 



77.96 
7&35 
76.44 
76.98 
77.62 
77.76 
79.32 
77.80 
7a 68 
80.27 
79.73 
78.04 



Per ct. 
8.68 
8.39 
9.26 
.8.39 
8.60 

11. 32 

12. 54 
14.51 
11.62 

7.61 

7.59 

7.-51 

7.43 

7.50 

6.81 

7.23 

7.53 

7.34 

7.43 

6. 

6. 



97 
96 
40 
54 

f^. 59 
6. 56 
6. 57 
6.56 
7.49 
7.13 
7.47 
1.03 
1.14 
1.06 



Per ct. 
.40 
.23 

.36 

.38 

.79 

1.02 

.94 

7.24 

1.10 

2.33 

2.24 

2.15 

2.36 

2.21 

2.30 

1.39 

.94 

1.18 

1.97 

1.46 

1.53 

1.06 

.95 

1.21 

2.04 

1.84 

2.04 

1.15 

1.50 

1.46 

.00 

.07 

• .07 



Carbo- 
hy- 
drates. 



Ash. 



Per c>. 
46.48 
46.61 
46.39 
45.96 
47.78 
77.31 
74.13 
67.61 
74. 43 
20.17 
20. 18 
20.45 

20. IS 
19. 13 
19. 84 
22.19 
22.95 
22.61 
22.06 
21.91 

■ 22.03 
23. 29 
22. ,50 
20. 96 
19. 4(i 

19. 69 
19.58 

21. 43 

22. 43 
21. 61 
21. 43 

20. 45 
21.78 



1.07 

1.06 

1.05 

1.10 

1. 19 

1.19 

.94 

.89 

1.01 

1.03 

.88 

1.15 



.03 
.03 
.05 
.05 
.05 
.05 
.09 
.09 
.09 
.14 
.11 
.08 



.35 



.27 



.04 



20.11 

19. 7(i 
21. 70 
21. 09 
20.43 

20. 28 
18.92 
20.48 
19.47 
17. 93 
18.57 
20. 02 

100. 00 
99. 65 



Per ct. 

0.87 

.80 

.72 

.96 

.84 

.42 

.51 

1.82 

.45 

2.40 

2.41 

2. 42 

2.44 

2. 30 

1.01 

2.50 

2.51 

2.70 

2.51 

2.69 

2. 15 

2.04 

2.79 

2.73 

1.69 

1. 61 

2.13 

2.58 

1.87 

2.40 

.78 

.75 

.84 



.83 
.80 
. 77 
.78 
.71 
.72 
.-73 
.74 
. 75 
.63 
.71 
.71 



100.00 
99. .53 



COMPOSITION or FECES. 

Separation of the feces pertainir.fr to a oriven experiment was made 
by means of lampblack, taken in gelatin capsnles at the beginning 
and the end of the experimental period. The total quantity of feces 
for each experiment was dried and ground and the samples for analysis 
were weighed from the total material thus prepared. In the first 8 
experiments the samples were analyzetl in the water-fi'ee condition, 
but in all the others thc}^ were in the air-dry condition, the methods 
of analysis being the same as in the case of the foods. Extraction 
with ether was continued for twenty-four hours, but it was difficult 
in some cases to get satisfactory results in this determination owing, 



11 

no doubt, to the fact that the feces contain substances other than fat 
which are sohible in ether. The data regarding the composition of 
the feces are given in Table 2. 

Table 2. — Composition of feces in the digestion experiments here reported. 



Lab- 
ora- 
tory 
No. 



758 

759 

760 

761 

762 

763 

764 

765 

794 

807 

818 

834 

846 

858 

870 

880 

891 

991 

992 

993 

994 

1089 

1090 

1115 

1128 

1129 

1138 

1139 

1156 

1157 

1223 

1227 

1231 

1248 

1252 

1291 

1295 

1299 

1318 

1322 

1.326 

1335 

1339 

1343 

1352 

1356 

1360 

1411 

1415 

1419 

1423 

1442 

1446 

1456 

1460 

1473 

1477 

1481 

1530 

1534 

1553 

1557 

1568 

1572 

1602 

1624 

1628 



Material. 



Feces, water-free. 

do 

do 

do 

do 

do 

do,. 

do 

Feces, air-dried . . 
do 



From ex- 
periment 
No.— 



-do. 
.do. 
.do. 
.do. 
.do. 
-do. 
.do. 
.do. 
-do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 



.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
-do. 
.do. 
.do. 



267 
269 
271 
273 
268 
270 
.272 
274 
275 
276 
277 
278 
279 
280 
281 
282 
283 
284 
285 
286 
287 
288 
289 
291 
290 
292 
293 
294 
295 
296 
297 
298 
299 
300 
301 
368 
369 
370 
371 
372 
373 
374 
375 
376 
377 
378 
379 
380 
381 
382 
383 
384 
385 
386 
387 
419 
420 
421 
422 
423 
424 
425 
426 
427 
428 
429 
430 



Per cent. 



Water. 



Protein 

(N.X 
6.25). 



Fat. 



6.21 
6.62 
7.26 
7.05 
7.71 
6.67 
7.46 
8.53 
9.12 
8.36 

10.83 
9.47 
9.05 
9.00 

10. .55 
6.82 

10. 48 
8.42 
9.59 
6.89 
7.12 
7.30 
8.40 

12.20 
7.47 

16.19 

14.23 
9.08 

15.39 

13.82 
8.46 

12.71 
7.90 
8.75 

11.87 
8.27 
9.85 

13.64 
8.63 

11.62 

12.90 

10.33 
6.98 

1.3.30 
4.63 
7.95 
6.06 
8.66 
7.33 
6.52 
8.87 
6.95 
8.63 
7.75 
6.64 
7.91 
9.13 
7.83 
8.681' 



Per cent. 
34.71 
34.63 
34.08 
34. 30 
25.83 
26.53 
27.82 
36.94 
.37. 77 
39.20 
36.30 
37.13 
37.12 
37.74 
40.46 
41. 37 
43.00 
36. 98 
34.72 
39.00 
.38. 25 
38.88 
36. 86 
28.00 
."^9. 51 
.33. 98 
38. 82 
26.04 
28.24 
27.55 
27.42 
29. 26 
22.49 
28.20 
29.78 
24.64 
27.67 
30. 15 
29.99 
34. 95 
27.42 
28.50 
30.40 
21.02 
28.47 
30.86 
22.76 
40.41 
32.03 
38.12 
28.81 
30.57 
21'. 32 
32.23 
23.82 
33.45 
24.92 
21.97 
21.23 
18.12 
29.95 
30.98 
17.84 
24.91 
26.23 
29.60 
35.27 



Carbo- 
hydrates. 



Ash. 



Per cent. 

14.17 

13.15 

13.19 

13.66 

7.71 

11.14 

9.81 

10.28 

10.71 

9.30 

12. 21 

7.87 

10.27 

10.12 

11.44 

12.41 

11.25 

7.15 

10.29 

7.42 

7.77 

7.76 

6.80 

12. 32 

10. 96 

13. 83 

8.67 

11.60 

12.05 

15.46 

12.28 

9.15 

9.25 

17.05 

10.72 

13.22 

23. 86 

22.16 

8.47 

8.87 

10.87 

6.93 

9.03 

6.55 

5. 76 

7.59 

6.26 

8.81 

8.73 

9.56 

9.70 

9.49 

9.92 

11.07 

8.36 

11.81 

11.64 

10.35 

12.30 

10.69 

10.76 

9.37 

7.56 

9.92 

10.25 

10.07 

10.52 



Per cent. 
36. 29 
37.82 
38.81 
36.70 
45.99 
42.88 
42.53 
41.64 
28.00 
27.68 
26.61 
29.54 
27.59 
27.77 
23. 52 
21.51 
21.09 
28.07 
26.91 
25.22 
28.34 
26.80 
30.09 
38. 05 
28.55 
28.43 
32. 37 
38.64 
38.73 
29.30 
28.59 
16.49 
38. 37 

6.66 
23.77 
33.66 

8.63 
21.23 
28.92 
14.21 
30. 23 
29.91 
18.05 
37.82 
20.96 
15.39 
35.97 
21.81 
31.04 
27.92 
36.80 
32. 42 
45.77 
28.45 
41. 39 
18. 03 
38.43 
40.95 
41.08 
45.64 
32.15 
30.23 
48.44 
38.26 
39.31 
36.63 i 
27.70 1 



Per 



cent. 
14.83 
14.40 
13.92 
15.34 
20.48 
19.45 
19.84 
21.13 
17.31 
17.20 
17.62 
18.41 
17.31 
17.70 
17.12 
16.18 
1.5. 54 
19.44 
17.25 
18.89 
16.59 
17.56 
15.70 
14.81 
10.50 
15. 34 
10.55 
16.83 
13.86 
20. 39 
23. 31 
.•^2. 90 
21.92 
31.90 
21.50 
19.40 
24.45 
12.64 
24.16 
29.26 
23.58 
25.91 
30.65 
26.34 
24.96 
32.52 
26. 38 
17. 35 
15.30 
14.07 
17.71 
14.22 
18.36 
20. .?0 
20.37 
28.05 
17.68 
20.21 
16.52 
18.60 
18.51 
21.67 
19.52 
19.00 
15.08 
15.87 
17.83 



12 

DETAILS OF EXPERIMENTS WITH MIXED DIET, INCLUDING 

MEAT. 

As previously suggested, one of the objects of the digestion experi- 
ments here reported was to determine what influence different meth- 
ods of cooking meat would have upon the digestibility of the total 
diet in which the meat was eaten. For this purpose 23 experiments 
were made in connection with the investigations conducted durinsr 
1898-1901 in wliich meat cooked in different ways constituted part 
of a mixed diet that included several common food materials. 

In selecting a diet for these experiments the problem was to obtain 
a ration containing such a variety of food materials that it would 
fairly represent an average mixed diet and be sufRciently palatable 
to be eaten for several days, but which should not include so many 
different kinds of food that the number of analyses would be unduly 
large. The foods selected were bread, butter, sugar, milk, rolled 
oats or wheat breakfast food, beans, and bananas, in addition to the 
meat. The diet made up of these materials proved quite satisfactory 
for all four subjects throughout all the tests. 

The 23 experiments here considered wer^ all alike in that the diet 
consisted of the same kinds of food materials, but they differed some- 
what in respect to the control of the quantity of food eaten and of 
the muscular activity of the subjects, and so the experiments have 
been arranged in three groups, in accordance with these variations. 

EXPERIMENTS WITH AMOUNTS OF FOOD NOT RESTRICTED. 

This group includes 8 experiments. The subjects were two young 
men, designated as A and B. Subject A was 35 years old and weighed, 
in ordinary clothing, about 170 pounds; subject B was 23 years old 
and weighed about 135 pounds. They were both in good health, 
had good appetites and apparently normal digestion. Both were 
chemists, and during the time of the experiments were engaged in 
their ordinary duties in the laboratory. 

Four experiments were made with each subject, in each case the 
corresponding experiments with the two subjects being carried on 
simultaneously. The daily food in the experiments consisted of a 
mixed diet of the materials mentioned above. The food materials were 
obtained as needed, and from each fresh portion a sample was reserved 
for analysis. The same kind and cut of meat, beef round, was used 
in every case, but it was differently cooked, as explained below. No 
attempt was made to regulate the quantities consumed, the subjects 
being allowed to eat at each meal according to their desires for the 
selected foods. There were noticeable differences in the amounts of 
the different foods eaten by the two subjects in corresponding (experi- 
ments and by the same subject in different experiments. 

Experiment No. 267, with subject A, and No. 268, with subject B, 
began with breakfast July 5, 1899, and continued four days (12 



13 



meals). Without any intermission between the two periods experi- 
ment No. 269, with subject A, and No. 270, with subject B, began 
with breakfast July 9, 1899, and continued three days (9 meals). 
The meat eaten in each experiment was beef round pan broiled (fried 
without added fat) for fifteen minutes. 

Experiments Nos. 271 and 272, with subjects A and B, respectively, 
began with breakfast July 19, 1899, and continued four days (12 
meals). In cooking the meat eaten in these two experiments it was 
placed in boiling water, and the temperature of the water was then 
maintained at 80° C. for two hours. 

Experiments Nos, 273 and 274, with subjects A and B, respectively, 
began with breakfast July 26, 1899, and continued four days (12 
meals). The meat in this case was placed in cold water, which was 
then heated and maintained at 65° to 70° C. for four hours. 

The data regarding the digestibility of the diets in these experi- 
ments are siven in Table 3. 





Table 3. — Results of digestion 


experiments Nos. 


267-274 






Labo- 
ratory 
No. 


Weight 
of mate- 
rial. 


Total or- 
ganic 
matter. 


Protein 

(NX6.25). 


Fat. 


Carbo- 
hydrates. 


Ash. 


609 


Experiment No. S67, subject A. 

Sugar 

Butter 

Milk 

[■Bread 

>Baked beans 


Grams. 

220 

220 

1,633 

715 

895 

1,200 
140 
360 


Grams. 
220 
196 
202 

411 

269 

265 
125 
106 


Grams. 


Grams. 


Grams. 
220 


Grams. 


620, 621 


1 
53 

53 

68 

13 
16 
95 


i95 
71 

21 

20 

1 
1 

11 


5 


622, 623 

614,616, 

617 

624,625, 


78 
337 

181 

251 
108 


11 
8 

22 


650, 651 

626,639 

608 


Bananas 

Breakfast food 


9 
1 


610-613 


Meat 

Total diet 


14 










5,383 
77 


1,796 
65 


299 
27 


320 
11 


1,175 

28 


70 


758 


Feces 

Amount digested 


11 






1,731 
96 


272 
91 


309 
96 


1,147 
98 


59 




Per cent digested ,L - . 


84 




Experiment No. "268. subject B. 

Sugar 

Butter 

Milk. 

[•Bread 

>Baked beans 






609 




60 

240 

4.916 

585 

761 

1,200 
140 
410 


60 
213 
609 

336 

228 

270 
125 
121 




60 




620,621 


1 
159 

43 

57 

13 

16 

108 


212 
214 

17 

17 

1 

1 
13 


5 


622,623 

614,616, 

617 

624,625, 


236 
276 

154 

256 
108 


34 

7 

18 


650, 651 

627,638 

608 


Bananas 

Breakfast food 


10 
1 


610-613 


Meat 


16 




Total diet 








8,312 
109 


1.962 
86 


, 397 
28 


475 

8 


1.090 
50 


91 


762 


Feces 


22 




Amount digested 








1,876 
96 


369 
93 


467 
98 


1,040 
95 


69 




Per cent digested 




75 




Experiment No. 269. .subject A . 
Sugar 






609 


160 
165 
1,175 
525 
600 
850 
105 
260 


160 

148 
152 
313 

180 

177 

94 

77 






160 

58' 

259 

122 

168 

81 




656, 657 


Butter 


1 
39 
41 
45 

9 
12 
69 


i47 
55 
13 
13 

i' 

8 


4 


670 


Milk 


9 


652,655 


Bread 


6 


650,651 


Baked beans 


14 


668 


Bananas 


9 


608 


Breakfast food 




610-613 


Meat 


10 




Total diet 








3,840 
53 


1,301 
46 


216 
1.8 


237 
7 


848 
20 


52 


759 


Feces 


8 




Amount digested 








1,255 
96 


198 
92 


230 

97 


828 
97 


44 




Per cent digested 


85 






. — 





14 



Table 3. — Results of digestion experiments Nos. ^67-'£74 — ("ontinued. 



Labo- 
ratory 
No. 




Weight 
of mate- 
rial. 


Total or- 
ganic 
matter. 


Protein 

(NX6.25). 


Fat. 


Carbo- 
hydrates. 


Ash. 


609 


Experiment No. g70. 

Sugar 

Butter 

Milk 

Broad 

Baked beans 


subject B. 

_ 




Grams. 
45 
180 
3,716 
450 
500 
850 
105 
300 


Orams. 

45 

161 

479 

269 

150 

180 

94 

88 


Grams. 


1 
1 
Grams. 


Grams. 
45 

i83' 

222 

102 

171 

81 


Grams. 


656,657 

670 

6.52.6.55 

650,651 


1 

124 

36 

37 

9 

12 
79 


160 

172 
11 
11 

r 

9 


4 
28 

5 
12 


660 


Bananas .... 




7 


60S 


Breakfast food 






610-613 


Meat 




12 




Total diet 








6.146 

77 


1,466 
62 


298 
20 


364 i 
9 


804 
33 


68 


763 


Feces 




15 




Amount digeste 
Per cent diirestoc 


d 








1,404 
96 


278 
93 


355 
98 


771 
96 


53 








78 




Kxperiment Xo. 371. 

Sugar 

Butter 

Milk 

Bread 

Baked l)eans 


.^ubjerf .1 . 






609 


240 
220 

l.,500 
700 
960 

1 . 400 
140 
400 


240 
195 
182 
413 
277 
320 
125 
140 






240 




713 


■ 1 
47 
55 
72 
15 
16 
116 


194 
62 
17 
21 

1 

1 

24 


4 


723 

710.712 

724 

722 


73 
341 
184 
304 
108 


11 

7 

22 

11 


608 


Breakfast food 




1 


716-718 


Meat 

Total diet 




14 




5.. 560 

78 


1.892 
67 


322 
V 27 


320 
10 


1,250 
30 


70 


760 


Feces 

Amount digested 

Per cent digested 


11 






1,825 
96 


295 
92 


310 
97. 


1,220 
98 


59 
84 




Experiment Xo. 273, 

Sugar 

Butter 

Milk 


subject B. 






609 
713 
723 


t;o 

180 
4.800 
5(50 
800 
1.400 
140 
440 


liO 
UiO 
.->S3 
330 
231 
311 
125 
155 


i' 

151 
44 
60 
15 
16 

128 


"'. '159' 

197 

13 

18 

1 

1 

27 


60 

235' 

273 
153 
295 
108 


4 

35 


710.712 
724 
721 

608 


Baked Iteans 

Bananas 

Breakfast food 


5 
18 
11 

1 


716,718 


Meat 

Total diet 




15 




8,380 
70 


1,956 
56 


415 
20 


416 

7 


1,124 
30 


89 


764 


Feces 

Amount digested 

Per cent digestec . 


14 






1.899 
97 


395 
95 


409 
98 


1,094 
97 


75 
84 




'Experiment Xo. 37.^. 

Sugar 

Butter 

Milk 


subject A 






609 
741 


24 

220 
.1.500 
710 
960 
1.400 
140 
400 


24 
19(i 
181 
428 
277 
302 
125 
134 


r 

-49 
.56 
65 
17 
16 
104 


195' 

57 
24 

22 

"l 

1 

30 


24 


4 


746 


75 
348 
190 
284 
108 


11 


735, 736 
747 


Bread 

Bakod lipans 


6 
16 


745 


BjHiiinas 




10 


608 


Brea.kfast food 




1 


739. 740 


Meat 




11 




Total diet . . . 






5.354 
51 


1.667 
43 


308 

17 


330 
7 


1,029 
19 


.59 


761 


' Feces 

.\mount digested 

Per cent digesteii 


8 






1.624 
•97 


291 
94 


323 

98 


1.010 
98 


51 

87 




Experiment No. 374 

Sugar 

Butter 

Milk 


subject B. 






609 


60 
180 

4.800 
560 
800 

1.400 
140 
440 


60 
160 
578 
338 
231 
304 
125 
147 






60 

239' 

274 
159 
286 
108 




741 
746 


1 
156 
45 
54 
17 
16 
114 


159 

183 
19 
18 

1 

1 

33 


4 
34 


735, 736 
747 


Bread 

Baked beans 


5 
1 13 


744 
608 


Bananas 

Breakfast food 


10 
1 


739, 740 


Meat 

Total diet 


12 










8.380 
63 


1.943 
49 


403 
17 


414 
6 


1.126 
26 


79 


765 


Feces 

Amount digested 

1 Per cent digested 


13 




1 

1 

1 


1,895 
97 

i 


386 
96 


1 408 
98 

1 


1.100 
98 


66 
83 



15 

The results of the foregoing experiments are summarized in Table 4. 
Table 4. — Summary of results of digestion experiments Nos. 267-274- 



Ex- 


Sub- 
ject. 


Diet. 


Total 
organic 
matter. 


Coefficients of digestibility. 


peri- 
ment 
No. 


Protein. 


Fat. 


Carbo- 
hydrates. 


Ash. 


267 
■^69 


A 
A 

B 
B 

A 
B 

A 
B 


Mixed diet, meat pan broiled 

do 


Per cent. 
96 
96 


Per cent. 
91 
92 


Per cent. 
97 
97 


Per cent. 
98 
97 


Per cent. 
84 
85 




Averasfe 






96 


91 


97 


97 


85 




Mixed diot meat Dan broiled 




968 


96 
96 


93 
93 


98 
98 


95 
96 


75 


270 


do 


78 




Averasre 






96 


93 


98 


95 


77 




Average 4 experiments with A 
and B 






96 


92 


97 


96 


81 




Mixed diet, meat cooked In water at 
80° C 




271 


96 
97 


92 
95 


97 
98 


98 

L 97 


84 


272 


do 


84 




Average. 


r 






96 


93 


97 1 97 


84 




Mixed diet, meat cooked in water at 
65-70° C 




273 


97 
97 


94 
96 


98 j 98 
98 98 


87 


274 


do : 

Average 


83 




97 


95 


98 98 


85 



There was striking uniformity in the digestibility of the total 
organic matter of the diets containing beef cooked in diiferent ways. 
In five experiments it was 96 per cent, and in three it was 97 per cent, 
showing that the diet as a whole was quite thoroughly digested in 
each case. In respect to the different nutrients also, the digestion 
of each was thorough and the agreement of results in the various 
experiments was satisfactory indeed. The indications are that under 
the conditions of these experiments the different methods of cooking 
the meat had no influence upon the digestibility of the diet as a whole. 
Possibly the amount of meat eaten was too small in proportion to that 
of the other materials to have much influence on the whole diet, 
though it will be noticed that in the majority of the experiments it 
furnished about a third of the total protein of the diet. 

EXPERIMENTS WITH DEFINITE AMOUNTS OF FOOD AND OF UNIFORM 

t 

MUSCULAR EXERCISE. 

In these experiments the attempt was made to control the condi- 
tions in such manner that, as nearly as possible, the only variation 
between the different experiments was in the method of cooking the 
meat. The same subject served throughout the whole series, and, 
except that the meat used was cooked in different ways, all the details, 
such as kinds and quantities of food consumed, daily routine of the 
subject, amount of exercise taken, etc., which it was believed might 
have some influence upon the general results, were maintained as 
4663— Bull. 193—07 2 



16 

uniform as possible in the different experiments. It seemed fair to 
assume that under such conditions whatever differences were found 
in the results of the experiments would be due in large part to varia- 
tions in digestibility of the meat brought about by different methods 
of cooking. 

The subject in these experiments was a young man in good health 
and with apparently normal digestion. He was a chemist, and was 
engaged in his ordinary duties in the laboratory, but kept his work as 
nearly as he could the same from day to day, and in addition he took 
a given amount of physical exercise regularly each day during an 
experiment. His weight in ordinary clothing was about 1 36 pounds. 

Nine experiments were made, each of four days' (12 meals) duration. 
There was in each case a period of several da^^s between the end of 
one experiment and the beginning of the next. The chief purpose 
of the first experiment, which was considered as preliminary to the 
series, was to allow the subject opportunity to decitle what kinds and 
quantities of food materials were most agreeable. The diet selected 
consisted of meat, bread, butter, sugar, beans, rolled oats, and milk. 
The meat used in all the experiments was lean beef round, cooked in 
different waj^s, as explained below. When eaten it was seasoned 
with salt and pepper. 

The same amount of each food material was eaten in all the experi- 
ments in the series proper. The diet in the preliminary test differs 
slightly from that in the others, the quantit}' of beans being a little 
larger and that of bread a little smaller, while wheat breakfast food 
was eaten in place of rolled oats. The actual difference in the diet 
was so small, however, that the results of this test may be taken into 
account with those of the remaining experiments. As during the 
preceding experiments, the food materials were obtained as wanted 
in each test and sampled when used. 

The preliminary experiment, No. 275, began with breakfast Decem- 
ber 2] , 1899. In cooking the meat used it was placed in boiling water, 
and the temperature of the water was then kept at 80° C. for two 
hours. Experiment No. 276 began with breakfast Januar}^ 3, 1900. 
The meat used was cooked in the same way as in experiment No. 
275. Experiment No. 277, which was a duplicate of No. 276, began 
with breakfast January 23, 1900. 

Experiment No. 278 began with breakfast February 20, 1 900. The 
meat used in this test was passed three times through a sausage mill, 
then made into balls and cooked by frying about ten minutes in a 
little melted butter, until medium well done. Experiment No. 279, 
whicli was a duplicate of experiment No. 278, began with breakfast 
March 12, 1900. 

Experiment No. 280 began with l)reakfast March 26, 1900. The 
meat used was placed in boiling water and then cooked twenty 



17 



minutes at 80° C. The cooked beef was ]mcj and undercione, but 
toiia^b. Experiment No. 281, a duplicate of No. 280, began with break- 
fast April 9, 1900. 

Experiment No. 282 began with breakfast April 23, 1900. The 
meat used was cooked by roasting or broiling a large piece, first sear- 
ing the surface for two or three minutes, then cooking for about 
twenty minutes, until medium well done. Experiment No. 283, a 
duplicate of No. 282, began with breakfast May 8, 1900. 

The data of these experiments are given in Table 5. 

Table 5. — Results of digestion experiments Nos. 275-283. 



Lab- 
ora- 
tory 
No". 




Weight 
of mate- 
rial. 


Total 
organic 
matter. 


Protein 

(NX6.25). 


Fat. 


Carbohy- 
drates. 


Ash. 


788 


Experiment No. 275. 
Sugar . . 


Grams. 
120 
180 
2,486 
140 
880 
780 
400 


Grams. 
120 
157 
314 
123 
271 
428 
163 


Grams. 


Grams. 


Grams. 
120 


Grams. 


786 


Butter 


1 
88 
18 
64 
57 
143 


1.56 

108 

1 

12 

7 

20 


4 


789 


Milk 


118 
104 
195 
364 


19 


787 


Breakfast food 


1 


784 


Beans. . 


22 


785 


B read 


6 


783 


Beef 

Total diet 


8 










4,986 
58 


1,.576 
44 


371 
22 


304 
6 


901 
16 


60 


794 


Feces (air dried) 

Amount digested 

Per cent digested 

Experiment No. 276. 

Sugar 


10 






1,532 
97 


349 
94 


298 
98 


885 
98 


50 
S3 


788 


120 
180 

2,486 
140 
840 
840 
400 
8 


120 
165 
301 
125 
263 
458 
172 




120 

107' 

95 
192 
389 




802 


Butter 


2 
86 
20 
63 
65 
140 


163 

ins 

10 
8 

4 


2 


801 


Milk 


19 


797 


Rolled oats 


.? 


800 


Beans 


21 


799 


B read 


11 


798 


Beef 


7 




Salt 


8 




Total diet. . 




1 








5,014 
76 


1,604 
58 


376 
30 


325 

7 


903 
21 


71 


807 


Feces 


13 




Amount digested 








1,546 
96 


346 
92 


318 
98 


882 
98 


.58 




Per cent digested 




81 




Experiment No. 277. 
Sugar 






788 


120 
180 
2,484 
140 
840 
840 
400 
7 


120 
1.53 
270 
125 
261 
467 
175 






120 




81.3 


Butter 


1 
66 
20 
61 
63 
145 


152 
84 
10 
10 
11 
. 30 


5 


812 


Milk ^ 


120 

95 

190 

393 


18 


, 797 


Rolled oats. . . 


3 


811 


Beans 


23 


810 




7 


809 


Beef 


11 




Salt 


7 




Total diet 














5,011 
43 


1,571 
32 


356 
'16 


297 
5 


918 
11 


74 


818 


Feces 


g 




.\mount digested 








1,.539 
98 


340 
96 


292 
98 


907 
99 


66 








90 




Experiment No. 278. 
Sugar 






788 


120 
180 
2,484 
140 
840 
840 
400 
9 


120 
160 
2&5 
125 
264 
485 
134 






120 




828 


Butter 


1 
68 
20 
62 
76 
107 


159 
89 
10 
17 
10 
27 


4 


829 


Milk 


128 

95 

185 

399 


18 


797 


Rolled oats. . . 


3 


827 


Beans 


21 


826 


Bread 


6 


825 


Beef 


• 9 




Salt 


9 




Total diet 














5.013 
34 


1,573 
26 


334 
13 


312 
3 


927 
10- 


70 


834 


Feces 


5 




Amount digested 








1,547 
98 


321 
96 


.307 
99 


917 
99 


65 




Per cent digested 




93 






: 





18 



Table 5. — Results of digestion experiments Nos. 215-28S — ContiiiiuHl. 



Lab- 
ora- 
tory 
No. 




Weight 
of mate- 
rial. 


Total 
organic 
matter. 


Protein 
(NX6.25). 


Fat. 


Carbohy- 
drates. 


Ash. 


788 


Experiment No. 279. 
Suerar 


Grams. 

120 
180 
2.480 
140 
840 
840 
400 


Grams. 
120 
158 
295 
125 
255 
476 
127 


Grams. 


Grams. 


Grams. 
120 

ii7' 

95 
184 
396 


Grams. 


837 


Butter 


1 
73 
20 
59 
71 
104 


157 

105 

10 

12 

9 

23 


5 


838 


Milk 


17 


797 


Rolled oats. 


3 


841 
840 
839 


Beans 

Bread 

Beef 

Salt 

Total diet 


23 

7 
6 






9 




i 










5.009 
27 


1,556 

21 


328 
10 


316 
, 3 


912 
9 


70 


846 


Feces 

Amount digested 

Per cent digested 


5 






1,535 
98 


318 
97 


313 
' 99 


903 
99 


65 
93 




Experiment No. 280. 

Sugar 

Butter 

Milk 

Rolled oats 






609 


120 
180 
2,482 
140 
840 
840 
400 
8 


120 
161 
296 
125 
256 
480 
142 




120 




852 


1 
69 
20 
58 
72 
115 


160 
108 
10 
13 
11 
27 


4 


853 
797 


121 

95 

185 

398 


18 
3 


851 
850 
849 


Bread 

Beef 

Salt 

Total diet 


18 
6 
6 






8 














5,009 
49 


1,583 
37 


» 335 
- 18 


329 
5 


919 
14 


63 


858 


Feces 


9 






1.546 
98 


317 
94 


324 
98 


905 
98 


54 




Per cent digested 

Experiment No. 281. 

Sugar 

Butter 

Milk. 




86 


609 


120 
180 
2,480 
140 
840 
840 
400 
7 


120 
161 
307 
125 
494 
485 
151 






120 




864 


1 
75 
20 
62 
68 
130 


160 

118 

10 

9 

21 


9 


865 


114 

95 

423 

410 


18 


797 


Rolled oats. .. . . .. . 


3 


863 


Beans 


22 


862 


B rea d 


7 


861 


Beef 

Salt 

Total diet 


6 






7 














5,007 
27 


1,843 
20 


356 
11 


325 
3 


1,162 
6 


65 


870 


Feces 


5 




Amount digested 








1.823 
99 


345 
97 


322 
99 


1,156 
99 


60 




Per cent digested 




93 




Experiment No. 282. 
Sugar . 






609 


120 
180 
2,478 
140 
840 
840 
400 
8 


120 
163 
277 
125 
260 
458 
127 






120 




874 


Butter 


1 
62 
20 
63 
70 
93 


162 

95 

10 

8 

6 

34 


2 


875 


Milk 


120 

95 

189 

382 


17 


797 


Rolled oats 


3 


873 


Beans 


23 


872 


Bread. 


6 


871 


Beef 

Salt 

Total diet 


5 






8 
















5,006 
50 


1,530 
38 


309 
21 


315 
6 


906 
11 


64 


880 


Feces 

-Vmount digested . 


8 






1,492 
97 


288 
93 


309 
98 


895 
99 


56 




Per cent digested 




87 




Experiment No. 283. 
Sugar ... 






609 


120 
180 
2,482 
140 
840 
840 
400 
H 


120 
164 
287 
125 
260 
479 
141 






120 




885 


Butter 

Milk 

Rolled oats 


1 
65 
20 
74 
76 
112 



163 
95 
10 
10 
7 
29 



4 


886 
797 


127 

95 

176 

396 


17 
3 


883 
882 
884 


Beans 

Bread 

Beef 

Salt 

Total diet 


23 
6 

(> 






11 




5.013 
49 


1,576 
37 


348 
21 


314 
(i 


914 
10 


70 


891 


Feces 


8 




Amount digested 








1,539 
98 


327 
94 


308 
98 


904 
99 


62 




Per cent digested 




89 











19 

The results of this series of experiments, including the preliminary 
test, are summarized in Table 6. 

Table 6. — Summary of result >< of duifstion experivwnts Nos. 275-283. 



Ex- 


Diet. 


Total 
organic 
matter. 


CoeiBcients of digestibility. 


peri- 
ment 
No. 


Protein. 


Fat. 


Carbohy- 
drates. 


Ash. 


275 
276 


Mixed diet, meat cooked in water, well done, 
.do 


Per cent. 
97 
96 

98 


Per cent. 
94 
92 
96 


Per cent. 

98 
98 
98 


Per cent. 
98 
98 
99 


Per cent. 
83 
81 


277 


do 


90 




Average 

Mixed diet, meat coolred in water, underdone 
do 






97 


94 


98 


98 


85 


280 

281 


98 
99 


94 
97 


98 
99 


98 
99 


86 
93 




A verage 






98 


96 


99 


99 


90 




Mixed diet, meat chopped and fried 




278 


98 
98 


96 
97 


99 
99 


99 
99 


93 


. 279 


do 

Average 

Mixed diet, meat roasted 


93 




98 


96 


99 


99 


93 


282 


97 
98 

97 


93 
94 


98 
98 


99 
99 


87 


283 


do 

Average 


89 




93 


98 


99 


88 









As in the previous series, the diet as a whole in these experiments 
was uniformly cjuite thoroughl}^ digested; and whether individual 
experiments or averages are considered, the variations in the results for 
the difl'erent nutrients are insignificant. The indications are that 
wdth this subject, under the conditions of the experiments, which 
though controlled were believed to be normal, differences in the 
method of cooking the meat had no effect upon the thoroughness of 
digestion of the diet in which it was eaten. 



EXPERIMENTS WITH VARYING AMOUNTS OF FOOD AND OF MUSCULAR 

EXERCISE. 

In the experiments of the preceding series the conditions in each 
case, even including the muscular activity of the subject, were main- 
tained as nearly as possible the same as in all the others, with the 
exception of the one, the effect of the variation of wliich it was desired 
to investigate, namely, the method of cookiiig the meat. In the fol- 
lowing experiments an attempt was made to learn whether variation 
in the amount of muscular exercise would have any effect upon the 
digestibility of the diet. 

The data are here given as 6 digestion experiments. There were, 
however, in reality 3 experiments, each of wliich was divided into two 
consecutive periods, in which the conditions were the same except that 
in the first period the subject abstained as entirely as possible from 
exercise of any kind, whereas in the second period he performed a con- 
siderable amount of muscular work. The diet in both periods con- 



20 

sisted of the same kinds of food materials, except that skimmed milk 
was used in some periods and whole milk in others. The amounts of 
the dilferent materials used in the two periods were so regulated that 
the quantity of protein per day was practically the same in the second 
period as in the first, but the quantity of energy was increased because 
of the work performed. 

Each of the 6 experiments continued four days (12 meals), except 
that No. 286 continued four and one-tliird days (13 meals). The sub- 
ject in all the experiments was a university student (C. A. S.), 21 years 
old, weighing without clothing a little over 140 pounds. The food 
consisted of a mixed diet containing meat cooked in every case by 
])lacing it in boiling water and then maintaining the temperature of the 
water at 80° to 85° C. for two hours. Instead of obtaining the food 
materials as wanted — as was done in the previous experiments — most 
of them were prepared at the beginning of each pair of experiments in 
quantities sufficient to last throughout both periods. 

Preparation of food. — In all the experiments the meat used w'as the 
best beef round, cooked in water as stated above. In preparing it for 
consumption the cooked meat was removed from the water, and after 
draining and cooling was ground in a sausage mill, in order that a rep- 
resentative sample might be obtained for analysis. The ground meat 
\vas then seasoned with salt and pepper, and passed t\dce more through 
the sausage mill, after which it was put immediately into glass jars, 
sterilized for one hour at 95° C, and placed in a refrigerator until 
needed. The sample for analysis was taken while the meat was being 
put into the jars; tliis was dried in a water bath at 70° to 90° C. for 
about forty-eight hours, and then exposed as usual to room tempera- 
ture and moist lu-e before weigliing again. When w^eighed the sample 
was finely ground for analysis. 

The bread used in the experiments (known locally as "Cream 
White ") was broken into fragments and sealed in tared glass fruit jars, 
weighed, sterilized at 95° C. for one hour and then placed in a refrigera- 
tor until wanted. The crust of the loaf was removed and only the 
crumb was used, as it w^as hoped thereb}^ to get a more uniform and 
representative sample for analysis. The sample was taken at the time 
the pieces of bread were put into the jars, and was prepared for analy- 
sis in the same manner as the meat described above. 

Creamery butter, purchased from one of the local grocers, was used. 
It was made into 1 -ounce pats, wliich were put upon plates to drain 
and kept in the refrigerator over night; one half of each pat was 
removed, and all these were mixed into a composite sample for analysis; 
the remaining portions of the pats were placed in small glass jars, 
w^eighed, and kept in the refrigerator until used. 

The mixed milk of a considerable number of cows was delivered 
from the University dairv as needed. The milk was found to be 



21 

always so well mixed that it was necessary to analyze only one 
sample for each experiment. 

Sugar and wheat breakfast food (one of the common commercial 
sorts) were w^eighed from a bulk of each as needed. The wheat 
brealvfast food for each meal was cooked by steaming. 

The bananas used were bought each day as needed. One-half of 
each banana used was placed in a glass jar containing a little forma- 
lin, and at the end of the experiment the whole composite sample 
thus formed was thoroughly mixed by grinding in a mortar. A large 
portion of the mixed mass was dried and ground for analysis. 

Canned baked beans were used, the contents of a number of cans 
being thoroughl}" mixed, then sealed in glass jars, and sterilized for 
one hour at 95° C. The jars were then placed in a refrigerator and 
kept until used. A sample for analysis was reserved from the mixed 
mass as it was being put into the jars. This was prepared in the 
same manner as the sample of meat described above. 

The sterilized foods were preserved in good condition in the refrig- 
'erator, and the subject selected the weighed jars as he needed them. 
The meat was warmed before using by steaming for fifteen minutes. 
The milk also was sometimes heated to 40° to 50°, according to taste. 
If any food remained in a jar at the close of the experiment it w^as 
weighed again and the amount deducted from the total. 

It was believed that to prepare the foods in the manner described 
gave better results than to w^eigli the food as needed from time to 
time, since errors in weighing that would result from loss of water 
occurring when food materials are kept exposed to the air would be 
prevented. Furthermore, it reduced the number of analyses con- 
siderably. 

Separation of feces. — The supper preceding the first meal of the first 
experiment and the breakfast following the last meal of the second 
experiment of each pair consisted of milk, with occasionally a little 
bread and butter, and with each of these meals lampblack in a gelatin 
capsule w^as taken. This gave blackened feces of a characteristic 
consistency preceding and following the feces pertaining to the 
experimental diet. It was assumed that none 'of the feces colored by 
the lampblack taken at these periods would pertain to the experi- 
mental diet. For separating the feces for"the first period from those 
for the second, the lampblack was taken after supper of the last meal 
of the first period. 

The urine in these experiments was collected in 6-hour periods, 
beginning with 7 o'clock on the morning of the first day of each 
experiment. 

Experiment No. 284 began w^th breakfast July 7, 1900. For the 
four days of this period the subject refrained as completely as prac- 
ticable from muscular exertion of any sort. Without intermission 



22 



experiment No. 285 began with breakfast July 11, 1900. During 
this period the subject was engaged for eight hours each day riding a 
bicycle over paved streets. The work involved in this exercise was 
liarder than that to which he had previously been accustomed. 

Experiment No. 286 began with breakfast July 21, 1900. The 
subject remained as quiet as practicable during the period. Experi- 
ment No. 287, following No. 286 without intermission, began with 
dinner July 25, 1900. The subject worked eight hours each day on a 
stationary bicycle. This work seemed to be even harder for him than 
that performed in experiment No. 285. 

Experiment No. 288 began with breakfast August 4, 1900. The 
subject did no actual work, but remained as quiet as practicable. 
In experiment No. 289, which began with breakfast August 8, 1900, 
the subject was at work eight hours each day on the stationary 
bic3xle. The work diu'ing this period did not seem as hard for him 
as that performed in experiment No. 2S7. 

The data of these six experiments are given in Table 7. 





Table 7. — Results 


of digestion experiments N 


OS. 284-289. 




Lab- 
ora- 
tory 

No. 




Weight 
of mate- 
rial. 


Total 
organic 
matter. 


Protein 

(NX0.25). 


Fat. 


Carbohy- 
drates. 


Ash. 


896 


Experiment No. 284- 

Sugar 

Butter 

Skim milk. 


Grams. 

80 

120 

5,805 
822 
640 
380 

1,200 
280 
700 


Gram.<<. 

80 

99 

465 

57 

357 

155 

. 239 

244 

196 


Grams. 


Grams. 


Grams. 
80 


Grams. 


902 


1 
182 
23 
53 
120 
11 
33 
46 


98 

23 
4 
6 

35 
1 
3 

14 




898 


260 

30 

298 


43 


027 
901 


do 

B read 


5 
5 


899 


Moat 


8 


926 

897 


Bananas 

Breakfast food 


227 
208 
136 


9 
1 


900 


Baked beans 


12 




Total diet. 






10,027 
126 


1,892 
91 


469 
47 


184 
9 


1,239 
35 


90 


991 


Feces 


25 




Amount digested 








1,801 
95 


422 
90 


175 
95 


1,204 
97 


65 




Per cent digested 




73 




Experiment No. 285. 
Sugar 






896 


160 
200 

3,418 
140 
820 
540 

1,600 
280 
900 


159 
165 
388 
10 
450 
224 
343 
244 
253 






159 




902 


Butter 


1 

115 

4 

66 

171 

14 

33 

59 


164 

126 

1 

6 

53 

1 

3 

17 


11 


928 


Whole milk . . . 


147 

5 

378 


25 


927 


Skim milk 


1 


924 


Bread 


7 


925 


Meat 


12 


950 


Bananas . 


328 
208 

177 


12 


897 


Breakfast food 


1 


923 


Baked bea ns 


15 




Total diet 






8,058 
86 


2,236 
62 


463 
30 


371 
9 


1,402 
23 


84 


992 


Feces 


15 




Amount digested 








2,174 
97 


43? 
93 


362 
98 


1,379 
98 


69 




Per cent digested 




82 




Experiment No. 286. 
Sugar 






896 


90 
130 

7,190 
690 
405 

1,350 
320 
700 


90 
108 
569 
379 
170 
278 
279 
197 


1 


90 




964 


Butter 


1 

223 
58 

137 
14 
37 
46 


107 

14 

4 

33 

1 

4 

14 


6 


985 


Skim milk 


332 
317 


.52 


962 


B read . 


7 


963 


Meat 


1 


986 




263 
238 
137 


;o 


897 


Breakfa st food 


1 


961 




15 




Total diet. 






10,875 
109 


2,070 
79 


516 
43 


177 
8 


1,377 
28 


98 


093 




21 












1,991 
96 


473 
92 


169 
95 


1,349 
98 


77 




P(*r cent digested 




79 











23 



Table 7. — Results of digestion experiments Nos. 284-289 — Continuod. 



Lab- 
ora- 
tory. 
No. 




Weight 
of mate- 
rial. 


Total 
organic 
matter. 


Protein. 

(NX6.25). 


Fat. 


Carbohy- 
drates. 


Ash. 


896 


Experiment No. 287. 
Sugar 


Grams. 
160 
200 

5,069 
780 
420 

1,600 
280 
800 


Grams 
1.59 
166 
576 
422 
170 
306 
244 
241 


Grams. 


Grams. 


Grams. 
159 


Grams. 


964 


Butter 


1 
164 
64 
144 
17 
33 
60 


165 
190 

4 
26 

2 

3 
9 


9 


990 


Whole milk 


222 
354 


36 


989 


Bread 


7 


988 


Meat 


14 


1026 


Bananas 


287 
208 
171 


10 


897 


Breakfast food . ... . 


1 


987 


Baked beans 


21 




Total diet 






9,309 

128 


2,284 
95 


483 
49 


399 
10 


1,402 
36 


98 


994 


Feces 


21 




Amount digested 








2,189 
96 


434 
<>0 


389 

97 


1,366 
97 


77 




Per cent digested 




78 




Experiment No. 288. 
Sugar . . 






,S96 


80 
120 

4,982 
640 
380 

1,200 
280 
700 


80 
98 
391 
354 
147 
235 
244 
217 






80 




10.32 


Butter 


15l 
56 

122 
11 
33 
50 


97 
5 
6 

2;, 
"l 

3 
10 


Q 


1031 


Skim milk 


235 
292 

208 
157 


37 


1030 


B read 




1029 


Meat 




1053 


Bananas 


s 


897 


Breakfast food 


1 


1028 


Baked beans ... 


I? 




Total diet 






8,382 
94 


1,766 
69 


424 
37 


147 

7 


1,195 
25 


79 


1089 




17 




Amount digested . . . 








1,697 
96 


387 
91 


140 
95 


1,170 
98 


62 




Per cent digested 




79 




Experiment No. 289. 
Sugar 






896 


160 
200 

3,316 
780 
420 

1,600 
280 
800 


159 

163 
367 
430 
170 
339 
244 
245 




159 




1032 


Butter 


1 
102 
66 
147 
18 
33 
60 


162 

121 

6 

23 

1 

3 

12 


10 


1057 


Whole milk . . . . . 


144 

358 


25 


1056 


B read 


6 


1054 


Meat 


9 


1088 


Bananas 


320 
208 
173 


11 


897 


Breakfast food . 


1 


1055 


Baked beans 


19 




Total diet. 






7,555 
92 


2,117 
68 


427 
34 


328 
6 


1,362 
28 


81 


1090 


Feces 


14 




Amount digested. .- . 








2,049 
97 


393 
92 


322 

98 


1,334 
98 


67 




Per cent digested 




82 











The results of these 6 experiments are summarized in Table 8. 
Table 8. — Summary of results (f digestion experiments Nos. 284-289. 



Ex- 


Kind of experiment. 


Coefficients of digestibility. 


peri- 
ment 
No. 


Total 
organic 
matter. 


t 
Protein. 


Fat. 


Carbohy- 
drates. 


Ash. 


284 
286 
288 


Rest experiments 

do 

do 

Average 

Work experiments 

do 

do 

Average 


Per cent. 
95 
96 
96 


Per cent. 
90 
92 
91 


Per cent. 
95 
95 
95 


Per cent. 
97 
98 
98 


Per cent. 
73 
79 
79 




96 j 91 


95 


98 


77 


285 
287 
289 


97 
96 
97 


93 
90 
92 


98 
97 
98 


98 
97 
98 


82 
78 
82 




97 


92 


98 


98 


81 













24 

As regards protein and carbohydrates, the average digestibility was 
practically the same (hiring the period when work was performed as 
when it was not. In the case of the fat, the average coefficient was 
slightly larger duritig the work period in each experiment. On the 
whole, the results indicate that meat, or a diet including a generous 
proportion of meat, was cpiite thoroughly assimilated by a subject per- 
forming a considerable amount of muscular work each day as well as 
when not working, and that the digestibility of the diet was not appre- 
ciably affected by the amount of muscular work performed. The 
latter deduction is in accord with those drawn by Wait °- and b}^ At- 
water and Sherman,'' from investigations on the effect of muscular 
work upon digestibilit3^ 

DETAILS OF EXPERIMENTS WITH SIMPLE DIET, INCLUDING 

MEAT. 

Experiments such as those considered above show the digestibility 
of the total diet including meat, but thev afford no indication of the 
digestibility of the meat itself. This may or may not be the same as 
that of the diet as a whole. It is very desirable, however, to know 
what proportion of the nutrients of meat will be digested when the 
meat is eaten in combination with other food materials. Particular 
attention was devoted to a study of this subject in connection with 
these investigations, and in all 44 experiments were made in which the 
digestibility of the meat was determined. 

In 21 of these experiments the same kinil and cut of meat — beef 
round — was cooked by different methods, namely, in water at 80° to 
85° C. for one, two, and three hours, and by pan broiling, frpng, and 
roasting; in 3 experiments beef shoulder was cooked in water for two 
hours; in 7 experiments beef ribs roasted were used; and in 13 experi- 
ments other kinds of meat, namely, veal, mutton, and pork, were 
cooked by roasting. 

The subjects in these experiments were eight young men, designated 
as A, B, D, E, F, H, I, and J. Subjects A and B were chemists, who 
had served in the experiments reported in preceding pages. Subjects 
D, E, F, and H were university students, aged 20, 22, 24, and 21 years, 
respectively, who were employed more or less in the laboratory. Sub- 
ject I was a high school pupil, 15 years old, who worked in the labora- 
tory during spare hours. Subject J was a janitor, 25 years old. All 
of the subjects were in good health, and none of them found the exac- 
tions of the experiments in any way disagreeable. Subject B served 
in 18 experiments; he was in nearly every one of the different series, 
which were continued at intervals through four years. The experi- 



oU. S. Dept. Agr., Office of Experiment Stations Bui. 89, p. 73. 
6U. S. Dept. Agr., Office of Experiment Stations Bui. 98, p. 56. 



25 

ments with the other subjects were practically duplicates or triplicates 
of those with liim. During this time liis weight varied from 135 to 
153 pounds, but in most of the experiments it was somewhere near 
145 pounds. The weight of subject E varied from 118 to 125 pounds, 
and that of I from 132 to 142 pounds, in the experiments in which 
they served. Subject A weighed about 170 pounds, D about 152 
pounds, F about 137 pounds, H about 140 pounds, and J about 130 
pounds in each experiment in which they served. 

Seven of the experiments continued two days, and all the others 
three days, as indicated later in the data of the experiments. In each 
case a very simple diet including the meat was eaten, as explained 
below, in order that the digestibility of the meat might be calculated. 

Experimental method. — The digestibility of single food materials is 
sometimes studied by experiments in which the diet consists only of 
the material under consideration. There are several objections to 
such a method, however. In the first place, it is generally difiicult to 
continue the experiment long enough to obtain satisfactory itsults, 
because no matter how palatable the single food may be at first, to the 
ordinarv individual accustomed to a mixed diet it commonlv becomes 
distasteful, and sometimes the digestive functions are disturbed to 
such an extent that the results of the experiment are impaired. In 
the second place, even if the diet could be endured for a sufficient 
length of time, the digestibility as thus determined might differ from 
that, of the same material when eaten in connection with other foods. 
As Prausnitz ** has pointed out, there are three possibilities: (1) Each 
food may be digested as it would be if used alone; or (2) the digesti- 
bility of one may be increased, or (3) it may be diminished by the 
addition of the others. In digestion experiments made in this country 
it has been observed that the digestion of foods in a mixed diet is 
commonly more complete than that of any of the foods when eaten 
alone. 

The question to be studied in these experiments mth meat was, as 
suggested above. What proportion of each of the nutrients of meats of 
different kinds and cooked in different ways would be digested when 
the meat forms part of a diet of ordinary food materials? It was 
believed that a tolerably accurate answer to this question could be 
obtained from experiments with a very simple diet in which meat 
formed a considerable proportion of the total food eaten. Such a 
diet may be consumed with comfort for a sufficient length of time, 
even when the number of foods is small, and it has been, found that 
in a diet of this character the nutrients are generally as thoroughly 
•digested as in one composed of a larger number of food materials. 
Furthermore, the digestibility of the nutrients of a given material in 
the simple diet may be calculated when that of the foods with which 



a Arch. Hyg., 17 (1893), p. 626. 



26 

it is eaten is known or may bo assumed. Woods " and Snyder'' liave 
in this way studied the digestibihty of bread from the results of experi- 
ments with bread and milk. The ingredients of the feces that would 
be derived from the milk they calculated by use of previously deter- 
mined factors for the digestibility of the milk, and assumed that the 
difference between these and the total ingredients of the feces would 
represent the ingredients due to the bread. 

A similar method was followed by the authors of this report in the 
series of experiments, with meat here considered. The diet consisted 
mainly of bread and meat, with milk or butter, or in some cases both, 
in addition. The subjects ate such quantities of any of these mate- 
rials as they desired at each meal, though it was- understood l)y all 
that the foods other than meat were eaten simply to keep the diet 
palatable and agreeable, and that the purpose was to have the meat 
form as large a proportion of the whole ration as was consistent with 
their comfort. The amounts of meat consumed by the same subject 
varied considerably in different experiments, principally because of 
differences in palatability due to different methods of preparation; 
but in all cases the quantity of meat eaten^formed a relatively large 
pro]5ortion of the total diet. Since the materials other than meat 
were few in number, and were those the digestibility of which may be 
assumed ^vith reasonable accuracy for the conditions of these experi- 
ments, it is possible to calculate quite satisfactorily the digestibility 
of the meat from the data obtained in the experiments. 

The digestibility of the diet as a whole was found in the usual 
manner by subtracting from the amount of each nutrient of the total 
diet the amount of the corresponding ingredient in the total feces. 
In order to compute the digestibility of the protein and fat of the 
meat alone it was necessary to assume certain more or less arbitrary 
factors for the digestibility of the other foods eaten with the meat. 
For the purpose of these investigations it was assumed that 89 per 
cent of the protein and 90 per cent of the fat of the bread would be 
digested, these factors being based upon the results of digestion 
experiments with bread carried on by Woods and Snyder (above 
referred to) in connection with the nutrition investigations of the 
Department of Agriculture. In studying the digestibility of bread 
it was assumed that 98 per cent of the protein and 99 per cent of the 
fat of the milk and butter eaten with the bread would be digested, 
and these factors have also been applied to the same materials in the 
present experiments. 

The method of estimating the digestibility of meat b)^ the applicati(m 
of the above factors to the foods other than meat may be illustrated 
by data from experiment No. 293. In this case 0.8 gram of the total 



aU. S. Dept. Agr., Office of Experiment Stations Bills. 85, 143. 

b\J. S. Dept. Agr., Office of Experiment Stations Buls. 101, 126, 156. 



27 

protein of the diet was derived from butter, of which 99 per cent was 
assumed to be digested, thus leaving a neghgible quantity in the feces; 
and 46.6 grams of protein were derived from bread, of which 89 per 
cent was assumed to be digested, leaving 5.1 grams in the feces. The 
total protein of the feces was 15 grams. . Subtracting from this the 
sum of the amounts calculated as due to bread and milk, 5.1 grams, 
would leave 9.9 grams of the protein of the feces as due to meat. 
The total quantity of protein digested from the meat would then be 
168.3 — 9.9=158.4 grams. Dividing this by the total in the meat 
consumed, 168.3 grams, and multiplying by 100, gives 94.1 per cent 
as the coefficient of digestibility of the meat protein. In like manner 
the digestibility of the fat of the meat was calculated. 

EXPERIMENTS WITH LEAN BEEF COOKED IN WATER FOR ONE HOUR. 

In the following 5 experiments the meat used consisted of lean beef 
round, which in each case was cooked in water at 80° to 85° C. for 
one hour. 

Experiment No. 293 with subject A and No. 294 with subject B 
began with breakfast December 8, 1900, and continued two days 
(6 meals). The diet consisted of meat, bread, and butter. The cut 
of meat used in these experiments was from an animal about 4 
years old. 

Experiments Nos. 297, 300, and 301 with subjects D, E, and B, 
respectively, began with breakfast August 21, 1901, and continued 
three days (9 meals). The diet consisted of meat, bread, butter, and 
milk. The meat was from an animal about 3 years old. 

The data of these experiments are given in Table 9. 

Table 9. — Results of digestion experiments with beef round cooked one hour in water at 

80 to 85° C. 



Lab- 
ora- 
tory 
No. 




Weight 
of mate- 
rial. 


Total 
organic 
matter. 


Protein 
(NX6.25). 


Fat. 


Carbohy- 
drates. 


Ash. 


1131 


Experiment No. 29S, subject A . 
Meat 


Orams. 
640.0 
tiOO.O 
135.0 


Grams. 
193.3 
.327. 9 
125.9 


Grams. 

168.3 

46.6 

' .8 


Grams. 

25.0 

2.3 

125. 1 


Grams. 


Grams. 
11.3 


1132 


Bread 


279. 1 


4.1 


1133 


Butter 


.5 




Total diet 






1,375.0 

38.8 


647.1 
30.9 


215.7 

15.0 

9.9 

200.7 
158.4 

93.0 
94.1 


152.4 
3.4 
1.9 

149.0 
23.1 

97.8 
92.5 


279.1 
12.5 


15.9 


1138 


Total feces 


4.1 




Estimated feces from meat 






Amomit digested: 
From total diet. 




616. 2 


266. 6 


11.8 




From meat alone 








Per cent digested : 

From total diet 




95.2 


95.5 


74.2 




From meat alone 








Experiment No. 29^, subject B. 
Meat 










1131 


7(i(). 5 

.500.0 

95.0 


231.5 

273.3 

88.6 


201.5 

38.8 

.6 


;?o.o 

1.9 
88.0 




13.5 


1132 


B read 


232. 5 


3.5 


1133 


Butter 


.3 




Total diet 








1,36L5 


593.4 


240.9 


119.9 


232.5 


17.3 



28 



Table 9. — Resitllx of digestion ex perlments with heef round cooked one hour in water at j; 

80 to 85° C— Continued. ' 



Lab- 
ora- 
tory 

No. 




Weight 
of mate- 
rial. 


Total 
organic 
matter. 


Protein 

(NX6.25). 


Fat. 


Carbohy- 
drates. 


.\sh. 


1139 


Experiment No. 294, subject B —Con. 
Total feces 


Orams. 
27.1 


Orams. 
20.7 


Grams. 
7.1 
3.8 

233.8 
198.7 

97.1- 
98.6 


Grams. 
3.2 
2.1 

116.7 
27.9 

97.3 
93.1 


Grams. 
10.5 


Gra ins. 
4 6 




Estimated feces from meat 






Amomit digested: 

From total diet 




5"72.6 


222.1 


12.7 




From meat alone 








Per cent digested: 

From total diet 




96.5 


95. 5 


73 6 




From meat alone 








Experiment No. 397, subject D. 
Meat 










1244 


1,000.0 

100.0 

1.8 

3, 073. 2 


297. 6 

.53.7 

1.6 

358. 6 


274.2 
7.2 

97." i" 


23.4 

.7 

1.6 

120.8 




16.2 


1233 


Bread 


45.8 


.7 


1208 


Butter 




1234 


Milk 


140.7 


21 2 




Total diet 






4,175.0 
21.5 


711.5 
14.7 


378.5 
.5.9 
3.2 

372.6 
271.0 

98.4 
98.9 


146.5 
2.6 
1.3 

143.9 
22.1 

98.2 
94.3 


186.5 
6.1 


38.1 


1223 


Total feces 


5.0 




Estimated feces from meat 






Amount digested: 

From total diet 




696.8 


180.4 


33.1 




From meat alone 








Percent digested: 

From total diet 




97.9 


96.7 


86.8 




From meat alone 








Experiment No. 300, subject E. 
Meat 








1244 


1,150.0 

500.0 

4,021.5 


342.2 
268. 6 
469.3 


315.3 

36.0 

127.1 


26.9 

3.7 

158.0 




18.6 


1233 


Bread 


228.9 
184.2 


3.4 


1234 


Milk 

Total diet 


27.7 




5,071.5 
55.6 


1,080.1 
28.9 


478.4 

15.7 

9.2 

462. 7 
306.2 

96.7 
97.1 


188.6 
9.5 

7.5 

179.1 
19.4 

94.5 
72.0 


413.1 
3.7 


49.7 


1248 


Total feces 


17.7 




Estimated feces from meat 






Amount digested: 

From total diet 




1,051.2 


409.4 


32.0 




From meat alone 








Per cent digested: 

From total diet 




96.5 


99.1 


64.3 




From meat alone 








Experiment No. 301, subject B. 

Meat 

B read 








1244 


1,050.0 

COO. 

50.0 

2, 353. 2 


312.5 

322.3 

44.2 

274. 6 


287.9 

4,3.2 

.3 

74.4 


24.6 

4.4 

43.8 

92.5 




17.0 


1233 


274.6 


4.0 


1208 


Butter 


.1 


1234 


Milk 


107.8 


16.2 




Total diet 






4,054.2 
37.6 


953.6 
24.2 


405.8 

11.2 

5.0 

394. 6 
283.0 

97.2 
98.3 


165.3 
4.0 
2.2 

161.3 
22.4 

97.6 
91.0 


382.4 
8.9 


37.3 


1252 


Total feces 


8.1 




Estimated feces from meat 






Amount digested: 

From total diet 


4,015.6 


929.3 


373.5 


29.2 




From meat alone 






Per cent digested: 

From total diet 




97.5 


97.7 


78.4 




From meat alone 



















EXPERIMENTS WITH LEAN BEEF COOKED IN WATER FOR TWO HOURS. 

In the five experiments followino; lean beef round cooked in water 
at 80 to 85° C, for two hours was used. 

Experiment No. 290, with subject A, and No. 292, with subject B, 
bejjan with breakfast November 21, 1900, and continued two days. 
Th(> diet consisted of meat, bread, and butter. Tlie cut of meat was 
from an animal about 6 years old. 

Experiment No. 291, with subject B, be<ji:an with breakfast Novem- 
ber 9, 1900, and continued two days. The diet consisted of bread, 
milk, and meat. The meat was from an animal about 5 years old. 



29 

Experiment No. 298, with subject E, and 299, with subject B, began 
with breakfast August 7, 1901, and continued three days. The (het 
consisted of bread, butter, and milk in adcHtion to the meat. The 
meat was from an animal about 3 years old. 

The data ot these experiments are given in Table 10. 

Table 10. — Results of digestion experirnenls with beef round eooked two hours in water 

at S0° to 8^° C. 



Lab- 
ora- 
tory 
No". 



1120 
1122 
1123 



1128 



1108 
1116 
1109 
1117 



1115 



1120 
1122 
1123 



1129 



iL'lii 
1207 
1208 
1209 
1232 



1227 





Weight 

of mate- 

lial. 


Total 
organic 
matter. 


Protein 

(NX6.25) 


Fat. 


Carl)ohy 
drates! 


Ash. 


Experiment No. 290, subject A . 
Meat 


Grams. 
560. 
549.8 
160.0 


Grams. 
211.9 
.?00. 3 
148.0 


Grams. 

176. 8 

43.4 

1.3 


1 Grams. 

35.1 

2.1 

146. 7 


Grams. 


Grams. 
10.2 
4.5 
.9 


Bread 


254.8 


Butter 


Total diet 


1 


1,269.8 
48.4 


660.2 
38.2 


221.5 
19.1 
14.3 

202.4 
162.5 

91.4 
91.9 


183.9 
5.3 
3.6 

178.6 
31.5 

97.1 
89.7 


254.8 
1:3.8 


15.6 
5.1 


Total feces 


Estimated feces from meat 


Amount digested: 

From total diet 


! 


622.0 


241.0 


10.5 


From meat alone 




Percent digested: 

From total diet 




94.2 


94.6 


67.5 


From meat alone 




Experiment No. 291, subject B. 
Meat 






. 




497.5 
235.0 
500.0 
775.5 


178.6 
89.0 

265.4 
78.5 


150.0 
79.4 
37.4 
23.3 


28.6 
9.6 
1.8 

22.8 




10.7 
5.2 
6.7 
5.4 


Meat 


" "226.2" 
32.4 


Bread 


Milk 


Total diet 


2,008.0 
38.3 


611.5 
30.0 


290.1 
10.7 

6.1 

279.4 
223.3 

96.3 
97.3 


62.8 
4.7 
4.3 

58.1 
33.9 

92.5 

88.7 


258.6 
14.6 
1.3.9 

244.0 


28.0 
5.7 


Total feces 


Estimated feces from meat 


Amount digested: 

From total diet 




581.5 


22.3 


From meat alone 




Percent digested: 

From total diet 




95.1 


94.4 


79.7 


From meat alone 






1 






Experiment No. 292, subject B. 
Meat 


780.0 
500.0 
100.0 


295.2 

273. 1 

92.5 


246.3 
39.5 

.8 


48.9 

1.9 

91.7 




14.3 

4.1 

.6 




231.7 


Butter 






Total diet 

Total feces 


1,380.0 
24.0 


660.8 
18.3 


286.6 
8.2 
3.9 

278.4 
242.4 

97.2 
98.5 


142.5 
3.3 
2.2 

139.2 
46.7 

97.7 
95.5 


231.7 
6.8 


19.0 
3.7 


Estimated frees from meat 


Amount digested: 

From total diet 




642.4 


224.9 


15.2 


From meat alone 




Percent digested: 

From total diet 




97.2 


97.1 


80.4 


From meat alone 














Experiment No. 298, subject E. 

Meat 

Bread 

Butter 


1.050.0 

800.0 

50.0 

2, 342. 6 

2,873.7 


348. 9 
442.0 
44.2 
250.7 
310. 7 


f 

323. 

59.7 

.3 

71.2 1 

81.3 


25. 9 
5.9 
43.8 
74.5 
96.8 


'"'376.' 4" 


17.0 

6.6 

.1 


Milk 


105.0 
132.5 


16.4 
19.0 


...do 1 


1 


Total diet 


7,116.3 
62.1 


1,396.5 
34.1 


535. 5 
18.2 

8.5 

1 

517.3 
314. 4 

90. 6 
97.4 


. 246.9 
5.7 
2.9 

241.2 
23.0 

97.7 

88.7 


613. 9 • 
10.2 


59.1 
20.4 


Total feces 


Estimated feces from meat 


Amount digested: 
From total diet.. 




1,.362.4 


603.7 


38.7 


From meat alone ' . 




Percent digested: 




97.6 ' 


98.3 


65.5 


From meat alone 






— '- 









30 

Tauij-: 10. — Results of diqestion expTriments with beef round rooked tvo hnvrs in water 

at 80° to 85° C— Continued. 



I-ab- 
ora- 
tory 
No. 




Weight 
of mate- 
rial. 


Total 
orgiinic 
matter. 


Protein 

(NX6.25). 


Fat. 

« 


Carbohy- 
drates. 


.Ash. 


1210 


Experiment No. 299, subject B. 
Moat 


Oram.s. 
900. 
• iOO. 
150.0 

2, 105. 3 


Grams. 
299.1 
331.5 
1.32. 5 
225. 3 


Grams. 

276. 8 

44.8 

1.0 

64.0 


Grams. 

22 2 

4.4 

131.5 

66.9 


Grams. 


Grams. 
14 6 


1207 


Bread 


282.3 


5 


1208 


Butter 


4 


1209 


Millc 


94.3 


14 7 




Total diet 






3, 755. 3 
52.0 


988.4 
36.7 


386.6 

11.7 

5.5 

374. 9 
271.4 

97.0 
98.0 


225.0 

4.8 
2.4 

220.2 
19.9 

97.9 
89.3 


376.6 
20.2 


34.7 
11 4 


1231 


Total feces .t- 




Estimated feces from meat 






Amount digested: 

From total diet 




951.7 


356. 4 


23.3 




From meat alone 








Per cent digested: 

From total diet 




96.3 


94.6 


67.1 




From meat alone 



















EXPERIMENTS WITH LEAN BEEF COOKED IN WATER FOR THREE HOURS. 

Two experiments, No. 295 -with subject A and No. 296 with subject 
B, were made with, lean beef round, from an animal about 2 years 
old, cooked in water at 80° to 85° C. for three hours. They began 
with breakfast January 18, 1901, and continued two days. 

The data of the experiments are given in Table 1 1 . 

Table 11. — Results of digestion experiments with beef round cooked three hours in water 

at 80° to 8.5° C. 



Lab- 
ora- 
tory 
No. 




Weight 
of mate- 
rial. 


Total 
organic 
matter. 


Protein 

(NX6.25). 


Fat. 


Carbohy- 
drates. 


Ash. 


1148 


Experiment No. 29.5. Subject A. 
Meat 


Grams. 
302.7 
(iOO. 
220. 8 
496.8 


Gram.'' 

125. 5 

311.3 

198.3 

54.0 


Grams. 

104. 

43.7 

1.3 

13.7 


Grams. 

21.5 

.9 

197.0 

17.9 


Grams. 

""26h'.7 


Grams. 
5.2 


1149 


B read 


5.3 


1150 


Butter 


1.6 


1151 


Milk 


22.5 


3.3 




Total diet 






1,620.3 
18.0 


689. 1 
14.3 




162.7 

5.1 

.3 

157.6 
103.7 

96.9 
99.7 


237.3 

2.2 

.1 

235.1 
21.4 

99.1 
99.5 


289.2 
7.0 


15.4 


1156 


Total feces 


2.5 




Estimated feces from meat 






Amount digested: 

From total diet 


1,602.2 


674.8 


282.2 


12.9 




From meat alone 






Per cent digested: 

From total diet 




97.9 


97.6 


83.8 




From meat alone 








Experiment No. 296, Subject B. 

Meat ^ 

B read 










1148 


4(K). 

488.3 

80.0 

1,135.5 


165.8 

253.4 

71.9 

123.4 


137.4 

35.5 

.5 

31.2 


28. 4 

.8 

71.4 

40.9 




6.8 


1149 


217.0 


4.4 


1150 


B utter 


.6 


1151 


Milk 

Total diet 

Total feces.. .. . ... 


51.3 


7.6 


1157 


2,103.8 
18.9 


614.5 
13.6 


204.6 
5.2 

.7 

199. 4 
136. 7 

97.5 
99.5 


141.5 
2.9 

1.7 

138. 6 
267.3 

97.9 
94.0 


268.3 
5.5 


19.4 
3.9 




Estimated feces from meat 






Amount digested: 

Froin totiil diot 


2, 084. 9 


600.9 


262.8 


15.5 










Percent digested: 
From tot;il diet 




97.8 


97.9 


79.9 




From nie>it nlono. 



















31 



EXPERIMENTS WITH LEAN BEEF PAN BROILED. 



The three following experiments were made \{^ith lean beef from 
an animal -about 3 years old. The meat was cut into steaks about an 
inch tliick, and pan broiled (fried without added fat) until well done. 
The cooked meat was then cut into strips, mixed with gravy obtained 
in cooking, seasoned to taste with salt and pepper, and then passed 
twice through a. sausage mill. As thus prepared it was fairly well 
relished by each subject. All the subjects ate bread and milk in 
addition to the meat, and subject F used a little butter also. 

Experiment No. 371, ^\dth subject F, and No. 372, with subject E, 
began with dinner March 18, 1901 ; and No. 373, with subject B, 
began with supper March 17. Each experiment continued three 
days (9 meals). The data of the experiments are given in Table 12. 

Table 12. — Results of digestion experiments with beef round pan oroiled. 



Lab- 
ora- 
tory 
No. 




Weight 
of mate- 
rial. 


Total 
organic 
matter. 


Protein 
(NX 
6.25). 


Fat. 


Carbohy- 
drates. 


Ash. 


1311 


Experiment JVb. 371, subject F. 
Milk 


Orams. 

3, 427. 04 

50.00 

600.00 

1, 100. 00 


Grams. 

394. 45 

44.45 

341. 58 

447. 70 


Grams. 

92.53 

.40 

56.04 

313. 06 


Grams. 

147. 70 

44.05 

3.24 

134. 64 


Grains. 
154. 22 


Grams. 
22.62 


1312 


Butter 


1.18 


1327 


Bread 


282. 30 


5.04 


1313 


Meat.. . 


28.28 




Total diet 










1,228.18 
40.32 


462. 03 

17.95 

9.93 

444. 08 
303. 13 

96.12 
96.83 


329. 63 
5.07 
2.83 

324. 56 
131. 81 

98.46 
97.90 


436. 52 
17.30 


57.22 


1318 


Total feces 


59.83 


14.45 




Estimated feces from meat 






Amount digested: 

From total diet 




1, 187. 86 


419. 22 


42.77 




From meat alone 








Percent digested: 

From total diet 




96.70 


96.03 


74.75 




From meat alone 








Experiment No. il2, subject E. 
Milk 











1311 


3,934.30 

700. 00 

1,200.00 


4.52. 84 
398. 51 
488. 40 


106. 23 

65.38 

341. 52 


169. 57 

3.78 

146. 88 


177. 04 
329. 35 


25.96 


1327 


Bread 


5.88 


1313 


Meat 


30.96 




Total diet 










1,339.75 
23.51 


513. 13 
14.16 

4.84 

498. 97 
330. 68 

97.24 
98.58 


320. 23 
3.59 
1.52 

316. 64 
14a 36 

98.88 
98.97 


506. 39 
5.76 


62. 80 


1322 


Total feces 


40.52 


11. 86 




Estimated feces from meat 






Amount digested: 

From total diet 






1,316.24 


500.63 


50.94 




From meat alone 








Percent digested: 

From tota 1 diet 




98.24 


98.86 


81.11 




From meat alone 








Experiment No. 373, subject B. 
Milk.. 








1311 


2, 64b. 58 

300.00 

1,200.00 


304. 63 
170. 79 
488.40 


71.46 

28. 02 

341. 52 


114. 07 

1.62 

146. 88 


119. 10 
141. 15 


17.46 


1327 


Bread 


2.52 


1313 


Meat 


30.96 




Total diet 










963. 82 
28.90 


441.00 

11.57 

7.06 

429. 43 
334. 46 

97.38 
97.93 


262. 57 
4.58 
3.28 

257. 99 
143. 60 

98.26 
97.77 


260. 25 
. 12.75 


50.94 


1326 


Total feces. . 


42.18 


9.95 




Estimated feces from meat 






Amount digested: 
From total diet. . 




934. 92 


247.50 


40.99 




From meat alone. . . . 








Percent digested: 

From total diet 




97.00 


95.10 


80.48 




From meat alone . 


















4663— Bull. 193—07- 



32 



EXPERIMENTS WITH LEAN BEEF FRIED. 

The 3 following experiments, Nos. 374 to 376, with subjects F, E, 
and B, respectively, began with breakfast April 2, 1902,^ and con- 
tinued three days (9 meals). The meat used was lean beef round 
from an animal about 3 j'ears old. It was cut into steaks about 
half an inch thick, then fried in hot lard until well done. The cooked 
steaks were cut into strips, seasoned to taste with salt and pepper, 
and passed twice through a sausage mill. The meat was rather 
dry and not very well relished by the subjects. All the subjects ate 
bread and milk in addition to the meat, and subject F used some 
butter also. Table 13 contains the data of the experiments. 

Table 13. — Results of digestion experiments with beef round fried in hot lard. 



Lab- 
ora- 
tory 
No. 




Weight 
of mate- 
rial. 


Total 
organic 
matter. 


Protein 
(NX 
6.25) . 


Fat. 


Carbohy- 
drates. 


Ash. 


1329 


Experiment No. 374, subject F. 
Milk 


Grams. 

3,805.00 

50.00 

557. 20 

800. 00 


Grams. 

445. 66 

44.45 

302. 11 

361. 52 


Grams. 

108. 82 

.40 

,51. 88 

271. 76 


Grams. 

161. 71 

44.05 

1.50 

89.76 


Grams. 
175. 03 


Grams. 
31.58 


1312 


Butter 


1. 18 


1328 


Bread 


248. 73 


4.63 


1330 


Meat 


20.64 




Total diet 










1, 153. 64 
35.45 


432. 86 
15.46 

7.58 

417. 40 
264. 18 

96.43 
97.21 


297. 02 
3.76 
1.55 

293. 26 
88.21 

98.73 
98.27 


423.76 
16.23 


58.03 


1335 


Total feces 


54.20 


14.06 




Estimated feces from meat 






Amomit digested: 

From total diet 




1, 118. 19 


407. 53 


43.97 




From meat alone 








Per cent digested : 

From total diet 




96.93 


96.17 


75. 77 




From meat alone 








Experiment No. 375, subject E. 
Milk 








1329 


3,651.22 
400. 00 
900.00 


427-56 
216.88 
406. 71 


104.42 

37.24 

305. 73 


155. 18 

1.08 

100. 98 


167. 96 
178. 56 


30.30 


1328 


Bread 


3.32 


1330 


Meat 


23.22 




Total diet 










1,051.15 
37.73 


447. 39 
19.95 
13.77 

427. 44 
291. 96 

95.54 
95.50 


257. 24 
5.93 

4.27 

251.31 
96.71 

97.69 
95.77 


346. 52 
11.85 


56.84 


1339 


Total feces 


65.03 


20. 12 




Estimated feces from meat 






Amomit digested: 

From total diet 




1,013.42 


334. 67 


36.72 




From meat alone 








Percent digested: 

From total diet 




96.41 


96.58 


04. 60 




From meat alone 








Experiment No. 376, subject B. 
Milk 










1329 


4,237.39 
300. 00 
700.00 


496. 20 
162. 66 
316. 33 


121. 19 

27.93 

237. 79 


180.09 

.81 

78.54 


194. 92 
133. 92 


35.17 


1328 


B read 


2.49 


1330 


Meat 


18.06 




Total diet 










975. 19 
27.60 


386. 91 
8.87 
3.37 

378. 04 
234.42 

97.73 
98.58 


259. 44 

2.77 
.89 

256. 67 
77.65 

98.93 
98.87 


328. 84 
15. 96 


55.72 


1343 


Total feces 


42.21 


11.12 




Estimated feces from meat 






From total diet. . . 




947. 59 


312. 88 


44.60 




From meat alone 








Percent digested: 
From total diet. 




97.17 


95.15 


80.04 




From meat alone 



















EXPERIMENTS WITH LEAN BEEF ROASTED. 

Experiments Nos. 377-379, with, subjects F, E, and B, respec- 
tively, began with breakfast April 16, 1903, and continued three days 
(9 meals). The meat used in these experiments was lean beef 



33 



round from an animal about 2 years old, roasted in an oven until 
well done. The cooked meat was cut into strips, mixed with gravy 
obtained in roasting, seasoned to taste with salt and pepper, and 
passed twice through a sausage mill. It had an excellent flavor 
and was relished by all the subjects. Table 14 gives the data of 
these experiments. 

Table 14. — Rvsults of digestion experivients with beef round roasted. 



Lab- 
ora- 
tory 
No. 




Weight 
of mate- 
rial. 


Total 
organic 
matter. 


Protein 

(N X 
6.25). 


Fat. 


Carboyh- 
d rates. 


Ash. 


1346 


Experiment No. 377, subject F. 
Milk 


Grams. 

3,950.19 

50.00 

400.00 

1,200.00 


Grams. 

478. 36 

43.96 

223. 04 

456. 84 


Grams. 

114. 15 

.23 

37.64 

357.24 


Grams. 

164. 33 

44.73 

2.36 

99.00 


Grams. 
199. 88 


Grams. 
29.03 


1345 


Butter 


1.20 


1344 


Bread 


183. 04 


2.88 


1347 


Meat 


38.40 




Total diet 










1,203.20 
22.83 


509. 26 
9.97 
3.55 

499.29 
353. 69 

98.04 
99.01 


311.02 
2.02 


382.92 
10.84 


72.11 


1352 


Total feces 


35.01 


8.73 




Estimated feces from meat . ... 






Amount digested: 

From total diet . . 




1,180.37 


309.00 
99.60 

99.33 
100. 00 


372.08 


63.38 




From meat alone 








Percent digested: 

From total diet 




98. 10 


97.17 


87.89 




From meat alone 








Experiment No. 378, subject E. 
Milk 










1346 


3,907.84 

300. GO 

1,000.00 


473. 24 
167. 28 
380.70 


112.94 

28.23 

297. 70 


162. 57 

1.77 

83.00 


197. 73 
137.28 


29.31 


1344 


B read 


2.16 


1347 


Meat 


32.00 




Total diet 










1,021.22 

18.86 


438. 87 

10.81 

5.45 

428.06 
292. 25 

97.54 

98.17 


247. 34 

2.66 

.86 

244. 08 
82.14 

98.92 
98.96 


335. 01 
5.39 


63.'47 


1356 


Total feces . . 


35.04 


11.40 




Estimated feces from meat 






Amount digested: 

From total diet . . . 




1,002.36 


329. 62 


52.07 




From meat alone 








Percent digested: 

From total diet 




98.15 


98.39 


82.04 




From meat alone 








Experiment No. 379, subject B. 

Milk 

B read 










134(i 
1344 


3, 407. 87 

.300. 00 

1,200.00 


412. 69 
167. 28 
456. 84 


98.49 

28.23 

357. 24 


141.76 

1.77 

99.60 


172. 44 
137. 28 


25.56 
2. 16 


1347 


Meat 


38 40 




Total diet 










1,036.81 
18.05 


483. 96 
6.32 
1.24 

477. 64 
356. 00 

98.69 
99.65 


243. 13 

1.74 

.15 

241. 39 
99.45 

99.28 
99.85 


309. 72 
9.99 


66. 12 


1360 




27.78 


7 33 




Estimated feces from meat 






Amount digested: 

From total diet 




1,018.76 


299. 73 


58. 79 




From meat alone 








Percent digested: 

From total diet 




98.24 


96.77 


88.91 




From meat alone 










1 







EXPERIMENTS WITH FAT BEEF COOKED IN WATER FOR TWO HOURS. 

Experiments Nos. 368-370, with, subjects F, E, and B, respectively, 
began \vith breakfast February 26, 1902, and continued three days 
(9 meals). The meat used in these experiments was fat beef shoulder, 
from an animal about 2% years old, cooked in distilled water at 80° 
to 85° C. for two hours. The cooked meat was relished by all the 
subjects throughout the experiments. The diet included bread and 
milk in addition to the meat, and subject F used some butter also. 
The data of the experiments are tabulated in Table 15. 



34 

Table 15. — Results of digestion experiments with fat beef shoulder cooked two hours in 

■water at 80^ to 85° C. 



Lab- 
ora- 
tory 
No. 




Weight 
of mate- 
rial. 


Total 
organic 
matter. 


Protein 
(NX 
6.2.5). 


Fat. 


Carbohy- 
drates. 


Ash. 


1285 

1286 


Experiment No. 368, subject F. 

Milk 

lUitter 


Grams. 

2,627.47 

50.00 

600.00 

1,400.00 


Orams. 

313.98 

45.26 

329.28 

686.98 


Grams. 

71.99 

.30 

51.66 

316.54 


Grams. 

109.57 

44.96 

5.28 

370.44 


Grams. 
132.42 


Grams. 
17.87 
1.33 


1281 


Bread. 


272.34 


5.28 


1287 


Meat 


•'2. 40 




Total diet 










1,375.50 
54.18 


440.49 
18.67 
11.55 

421.82 
304.99 

95.76 
96.35 


533.25 

10.01 

7.94 

520.24 
362. 50 

98.11 
97.86 


404. 76 
25.50 


46.88 


1291 


Total feces 


75.76 


14.70 




Estimated feces from meat 






Amount digested: 

From total diet 




1,321.32 


379.26 


32.18 




From meat alone 








Per cent digested : 

From total diet 




96.06 


93.70 


68.64 




From meat alone 








Experiment No. S69, subject E. 
Milk 










» 

1285 


2,832.84 
793.61 
590.00 

1,403.00 


338.52 

79.35 

274.45 

683.98 


77.62 

18.09 

43.05 

316.54 


118.13 

22.14 

4.43 

370.44 


142.77 

39.13 

226.95 


19.26 


1301 


do 


5.32 


1284 


Bread 


4.40 


1287 


Meat . . 


22.40 




Total diet 










1,379.26 
40.53 


455.33 
18.63 
^1.98 

436.67 
304.56 

95.91 
96.22 


515.11 
16.06 
14.22 

499.05 
356.22 

96.88 
98.16 


408.85 
5.81 


51.38 


1295 


Total feces 


67.32 


16.46 










Amount digested: 

From total diet 




1,338.76 


403.04 


34. 92 




From meat alone 








Percent digested: 
From total diet 




97.06 


98.58 


67.96 




From meat alone 








Experiment No. 370, subject B. 
Milk 










1285 


1,035.10 

400.00 

1,503.00 


123.69 
219.52 
736.05 


28.36 

34.44 

339. 15 


43.16 

3.52 

396.90 


52.17 
181.56 


7.04 


1284 
1287 


Bread 

Meat 


3. 52 
24.00 




Total diet 










1,079.26 
29.98 


401.95 

12.29 

7.93 

389.66 
331.22 

96.94 
97.67 


443.58 
9.04 
8.26 

434.54 
388.64 

97.97 
97.92 


233. 73 
8.65 


34.56 


1299 


Total feces . . . . 


40.76 


5.15 




P-stimated feces from meat 






Amount digested: 
From total diet 




1,049.28 


225.08 


29.41 




From meat alone 








Percent digested: 

From total diet 




97.22 


96.30 


85.10 




From meat alone . . . 



















EXPERIMENTS WITH BEEP RIBS ROASTED. 

In the following 7 experiments the cut of meat used w^as beef ribs, 
roasted in a gas oven until well done. The bones and surplus fat were 
removed from the roasted meat, and the remainder was used. The 
diet in each case included bread, butter, and milk in addition to the 
meat. Each experiment continued three days (9 meals). 

Experiments Nos. 422 and 423, \\nth subjects I and B, began with 
breakfast December 31, 1902. The meat used was from a 4-year-old 
Shorthorn cow in prime condition at the time of slaughter. Experi- 
ments Xos. 426 and 427, with subjects B and J, began wdth breakfast 
January 21, 1903. The meat used was from a 2-year-old Aberdeen- 
Angus cow, in rather thin condition at the time of slaughter. Experi- 
ment No. 428, with subject B, began mth breakfast January 28, 1903. 



35 

The meat used was from a yearling Aberdeen- Angus steer in prime 
condition at the time of slaughter. Experiments Xos. 429 and 430, 
with subjects B and J, began with breakfast February 4, 1903. The 
meat used was from a well-fattened animal. Table 16 contains the 
data of these experiments. 





Table 16. — Results of digestion experiments ivith bt 


;e/ ribs roasted. 




Lab- 
ora- 
tory 
No. 


': Weight 
of mate- 
rial. 


Total 
organic 
matter. 


Protein 

(N X 
6.25) . 


Fat. 


Carbohy- 
drates. 


Ash. 


1523 
1524 
1526 


Experiment No. 4-1?, subject T. 

Milk 

Bread 

Butter 

Meat, 


Grams. 

4,037.77 
800. 00 
100. 00 

1,100.00 


Grams. 

o3S. 24 

444. 48 

84.80 

595. 43 


Grams. 

131. 23 

09. 44 

.55 

220. 44 


Grams. 

220. 56 

3.20 

84.25 

374. 99 


Grams. 
176. 45 
371. 84 


Grams. 
26.25 
6.96 
9 37 


1525 




21.23 










Total diet .' 




1,66.3.05 
44. .38 


421.66 

12.63 

2. .37 

409.03 
218. 07 

97.00 
98.92 


693. 10 
7. 32 
.3.85 

685. 78 
.371. 14 

98.94 
98.97 


548. 29 
24.43 


56.81 


1530 


Total feces. . . . . 


59.48 


9.83 




Estimated feces from meat 






Amount digested: 

From total diet 




1,618 67 


523. 86 


46.98 




From meat alone 








Percent diarested: 
From total diet 




97.32 


95.54 


82.70 




From meat alone 








Experiment No. 4.?3, subject B. 
Milk 


1 






1523 


3, 658. 29 

800 00 

50.00 

1, 100. 00 


487. 65 

444. 48 

42.45 

595. 43 


118. 89 

69.44 

.28 

220. 44 


208.89 

3.20 

42.17 

374.99 


159.87 
371. 84 


23.78 


1524 


Bread 


6.96 


1526 


Butter 

Meat 

Total diet 

Total feces 


1.18 


1525 




21.23 








1534 


""60.' 97" 


1,570.01 
45.39 


409. 05 

11.05 

1.03 

398.00 
219. 41 

97.30 
99. 53 


629. 25 
6.51 
3.68 

623. 74 
.371. 31 

99.12 
99.02 


531. 71 
27. 83 


53.15 
11. .34 




Estimated feces from meat . ... 






Amount digested : 

From total diet 




1,524.62 


503.88 


41.81 




From meat alone 








Percent digested: 

From total diet 




97.11 


94.77 


78.66 




From meat alone 








Experiment No. 126, subject B. 
Milk 










1562 


3,858.48 
700 00 
100 00 

1, 100. 00 


463. 01 

392. 07 

86. CO 

471. 35 


115. 75 

64.82 

.70 

271. 04 


170. 54 

2.52 

85.60 

200. 31 


176. 72 
324. 73 


27.01 


1563 


Bread 


5.04 


1564 


Butter 


2.38 


1561 


Meat 




28.05 




Total diet 










1, 413. 03 
38.11 


452 31 
9.21 
2.08 

443. 10 
268. 96 

97.96 
99. 23 


459. 27 
3.90 
1.08 

455. 37 
199. 23 

99.15 
99.46 


501. 45 
25. 00 


62.48 


1568 


Total feces 


51.62 


10.08 




Estimated feces from meat 






Amount digested: 

From total diet 




1,. 374. 92 


476. 45 


.52. 40 




From meat alone 








Per cent digested: 

From total diet 




97.30 


95.02 


83.87 




From meat alone 








Experiment No. 437, subject J. 

Milk 

B read 

Butter 

Meat 

Total diet 


! 






1562 
1563 
1564 


2,863.85 
800.00 
100.00 

1,. 500. 00 


343 66 

448.08 

86.60 

642.75 


85.92 

74.08 

.70 

369.60 


126.58 

2.88 

85.90 

273. 15 


131.16 
371.12 


20.05 
5.76 
2.38 


1561 


- ... - 


38.25 






1,. 521. 09 
18.72 


530. 30 
6.38 


488.51 

2.54 

.13 

485.97 
273.02 

99.48 
99.95 


.502. 28 
9.80 


66.44 


1572 


Total feces 


25.62 


4.87 




Estimated feces from meat 






Amount digested: 

From total diet 




1,502.37 


523.92 
369.60 

98.80 
100.00 


492.48 


61.57 




From meat alone 








Percent digested: 

From total diet 


98.77 


98.05 


92.67 




From meat alone 















36 



Takt;E 1(i. — Results of digestion experiments iidth beef ribs roasted — Coutimu'd. 



Lab- 
ora- 
tory 

No. 




Weight 
of mate- 
rial. 


Total 
org.inic 
matter. 


Protein 

(NX 
6.25). 


Fat. 


Carbohy- 
drates. 


Ash. 


1597 


Experiment No. 4^8, subject B. 
Milk 


Grams. 

2,426.80 
500.00 
100.00 

1,100.00 


Grams. 

292.43 

273.65 

89.00 

534.82 


Grams. 

73.29 

41.95 

.67 

226. 16 


Grams. 

100.95 

1.90 

88.33 

308.66 


Grams. 
118.19 
229.80 


Grams. 
16.02 


1596 


B read 


4.80 


1598 


Butter 


2.38 


1595 


Meat 

Total diet 


26. 06 












1,189.90 
29.03 


342.07 

10.05 

3.97 

332.02 
222. 19 

97.06 
98.25 


499.84 
3.92 
1.84 

495.92 
306.82 

,99.22 
99.40 


347.99 
15.06 


49.27 


1602 


Total feces 


38.30 


5. 77 




Kstimated feces from nieat 






Amount digested : 

From total diet 




1,160.87 


332.93 


43.50 




From meat alone 








Per cent digested : 

From toliil diet 


• 


97.55 


95.67 


88.29 




From meat alone 








Erperiment No. 4^9, subject B. 
Millc 






1 


1619 


3,488.72 

700.00 

50.00 

1,100.00 


414.46 

400. 19 

44.45 

597.30 


104.31 

60. 20 

.41 

259. 93 


146.53 

5.53 

44.04 

337.37 


163.62 
334.46 


23.72 


1618 


B read 


5.88 


1620 


Butter... 


1.01 


1617 


Meat 




25.74 




Total diet 








1,456.40 

17.81 


424.85 

6.91 

.29 

■ft7.94 
259.64 

98.37 
99.89 


533.47 
2.35 


498.08 
8.55 


.56. 35 


1624 


Total feces 


23.35 


3.71 




Estimated feces from meat 






Amount digested: 

From total diet 




1,438.59 


.531. 12 
3.37.37 

99.56 
100.00 


489.53 


52.64 




From meat alone 








Percent digested: 
From total diet 




98.78 


98.28 


93.42 




From meat alone 








Experiment No. 430, subject J. 
Milk 










1619 


2,827.99 
800.00 
100.00 

1,600.00 


335.97 

457.36 

86.91 

868.80 


84.56 
68. 80 

.82 
378.08 


118.78 

6.32 

86.09 

490. 72 


132.63 
382.24 


19.23 


1618 


B read . 


6.72 


1620 


Butter 


2.02 


1617 


Meat 


37.44 




Total diet 






• 




1,749.04 
41.28 


532.26 
19.81 
10.47 

512.45 
367.61 

96.28 
97.23 


701.91 
5.91 
3.23 

696.00 
487.49 

99.16 
99.34 


514.87 
15.56 


65.41 


1628 


Total feces . . 


56. 18 


10.02 




Estimated feces from meat 






Amount digested: 

From total diet 




1,707.76 


499.31 


55.39 




From meat alone 








Per cent digested : 

From total diet 




97.64 


96.98 


84.68 




From meat alone 



















EXPERIMEIS^TS AVITII FAT VEAL LEG ROASTED. 



In these 6 experiments the meat used was very fat veal leg, roasted 
in a gas oven until well done, and seasoned to taste with salt and 
pepper. The cooked meat was relished by each subject throughout 
the experiments. 

Each experiment continued thi-ee days (9 meals). All the sub- 
jects ate bread and milk in addition to the meat, and subjects I 
and B used butter also. Experiments Nos. 380, 382, and 383, with 
subjects H, I, and B, respectively, began with breakfast September 
24, 1902. The meat used was from a calf about 10 weeks old. Ex- 
periments Nos. 419-421, with subjects H, I, and B, began with 
breakfast December 10, 1902. The data of these experiments are 
given in Table 17. 



37 



Table 17. — Results of digestion experiments with veal roasted. 



Lab- 
ora- 
tory 
No. 




Weight 
of mate- 
rial. 


Total 
organic 
matter. 


Protein 
(NX 
0.25). 


Fat. 


Carbohy- 
drates. 


Ash. 


1405 


Experiment No. S80, subject H. 
Milk 


Grams 
1,361.95 
1, SCO. 43 
350.00 
1,300.00 


Grams. 
180.86 
216.55 
192. 61 
580. 84 


Grams. 

43. 17 

56.56 

31.68 

365. 56 


Grams. 

72.86 

71.81 

1.36 

21.5.28 


Grams. 

64.83 

88.18 

1.59.57 


Grams. 
9.81 


1429 


do . . 


12. 47 


1404 


Bread . 


3.01 


1406 


Afpnt 


30.42 




Total diet 










1,170.86 
32.36 


496.97 
18.41 
12.93 

478. 56 
.3.52.63 

96.30 
96.46 


361.31 
4.01 
2.43 

357.30 
212. 85 

98.89 
98.87 


.31 2. .58 
9.94 

302. 64 

96.83 


.55. 71 


1411 


Total feces 


45.56 


7.91 




Kstimnted fece.s from meat 






Amount digested: 

From total diet 




1,138.50 


47.80 




Krom moi)t alone 








Percent digested: 
From total diet 




97.24 


85.80 






















1405 
1429 
1404 


Experiment No. S82, subject I. 
Milk 


1,3.52.67 

1,870.76 

900.00 

150. 00 

1,600.00 


179. 64 
217. 76 
495. 27 
125. 26 
714.88 


42.88 

.56. 87 

81.45 

1.23 

449. 92 


72. 37 

72.21 

3.51 

124.03 

264. 96 


64.39 

88.68 
410. 31 


9.74 


do 


12. .53 




7.74 


1407 


■Rnttpr 


4.32 


1406 






37.44 














1,732.81 
42. 34 


632.35 
21. 35 
10.38 

(ill. 00 
439. 54 

96.62 
97.69 


537. 08 
5. 35 
2.31 

.531. 73 
262. 65 

99.00 
99.13 


563. 38 
15.64 


71.77 


1419 


Total feces . 


56.00 


7.88 










Amount digested: 

From total diet 




1,690.47 


547.74 


63.89 












Per cent digested: 

From total diet 




97. .55 


97.22 


89.02 




FroTTi mpfit filonp. 








Ezperiwent No. 3,SS. subject B. 
MUk 


1 






1405 


632.00 
1,301.58 

400. 00 

.50. 00 

1,200.00 


S3. 93 
151.. 50 
220. 12 

41.76 
536. 16 


20.04 

39. 57 

36. 20 

.41 

337. 44 


.33.81 

50. 24 

1.56 

41.35 

198. 72 


30.08 

61.69 

182. 36 


4.55 


1429 


....do 


8.72 


1404 


B read 


3.44 


1407 


Butter . . . . 


1.44 


1406 


Meat 




28.08 




Total diet. 










1,033.47 
2.5.93 


433. 66 
9.92 
4.74 

423. 74 
332. 70 

97.71 
98. 59 


325. 68 
3.34 
1.93 

322.34 
196. 79 

98.97 
99.03 


274. 13 
12.67 


46.23 


1423 


Total feces 


34.42 


6.09 




Estimated feces from meat .... 






Amount digested: 

From total diet 




1,007.54 


261.46 
95.38 


40.14 




From meat alone 








Percent digested: 

From total diet 




97.49 


86.83 




From meat alone . 






1466 

1467 


Experiment No. 419, subject H. 
Milk 










3,808.22 

600.00 

1,000.00 


462. 70 
321.72 
317.20 


119.20 

48.06 

283. SO 


167.94 

2.40 

33.40 


175.56 
271.26 


27.42 


Bread... . . . 


4.92 


1469 




24.70 














1,101.62 
25.18 


451.06 

13.31 

5.64 

437. 75 
278. 16 

97.05 
98.01 


203. 74 
4.70 

2.78 

199.04 
30.62 

97.69 
91.67 


446. 82 
7.17 


57.04 


1473 


Total feces 


39.79 


11.16 










Amount digested: 




1,076.44 


439.65 


45.88 




From meat alone. 








Per cent digested : 

From total diet 




97.71 


98.40 


80.43 




From meat alone. . 








Experiment No. 420, subject I. 
Milk. . . . 








1466 


3,994.34 
700.00 
150.00 

1.100.00 


485.31 
375.34 
132. 83 
348.92 


125.02 

56. 07 

.83 

312. 18 


176. 15 

2.80 

1,32. 00 

36.74 


184. 14 
316. 47 


28.76 


1467 


Bread 


5.74 


1468 


Butter 


2.43 


1469 


Meat 




27.17 




Total diet... . 










1,342.40 
19.29 


494. 10 

6.41 

.24 

487. 69 
311.94 

98.70 
99.92 


347.69 
2.99 


500.61 
9.89 


64.10 


1477 


To*^al feces 


25.73 


4.55 




Estimated feces from meat 






Amount digested : 

From total diet 




1,323.11 


344. 70 
36.74 

99.14 
100.00 


490. 72 


59.55 




From meat alone. . . . ' 






Per cent digested : 

From total diet 




98.57 


98.02 


92.90 




From meat alone 



















38 

Table 17. — Results of digestion expenments with veal roasted — Continued. 



Lab- 
ora- 
tory 

No. 




Weight 
of mate- 
rial. 

Grams. 

2,574.66 
700.00 
100.00 

1,000.00 


Total 
organic 
matter. 


Protein 
(Nx 
6.25). 


Fat. 


Caibohy- 
drates. 


Ash. 


1466 
1467 


Experiment ^o. 4?1, gtibjeci B. 

Milk 

Bread 


Grams. 

312.82 

375. 34 

88.55 

317.20 


Grams. 

80.59 

.56.07 

.55 

283.80 


Grams. 

113.54 

2.80 

88.00 

33.40 


Grams. 
118.69 
316. 47 


Grams. 
18.54 
5.74 


1468 


Butter 


1.62 


1469 


Meat 




24.70 




Total diet 










1,093.91 
19.69 


421.01 
5.90 


237. 74 

2.78 

.48 

234.96 
32.92 

'98.83 
98.56 


435. 16 
11.01 


50.60 


1481 


Total feces 


26.87 


5. 43 




Estimated feces from meat 






Amount digested: 

From total diet 




1,074.22 


415. 11 
283.80 

98.60 
100.00 


424. 15 


45.17 




From meat alone 








Per cent digested : 

From total diet 




98.20 


97.47 


89.27 




From meat alone . . .- 



















EXPERIMENTS WITH MUTTON LEG ROASTED. 

Experiments Nos. 381, 384, and 385, with subjects H, I, and B, 
respectively, began with breakfast October 8, 1902, and continued 
three days. All the subjects ate bread, milk, and meat, and subjects 
I and B added butter. The meat was very fkt leg of mutton, from an 
animal about 1 year old, roasted in a gas oven until well done, and 
was well relished by each subject. Subject H felt somewhat indis- 
posed toward the close of the experiment. The data of the experi- 
ments are given in Table 18. 

Table 18. — Results of digestion experiments with mutton roasted. 



Lab- 
ora- 
tory 
No. 




Weight 
of mate- 
rial. 


Total 
organic 
matter. 


Protein 
(NX 
6.25). 


Fat. 


Carbohy- 
drates. 


Ash. 


1435 


Experiment No. S8t, subject H. 
Milk 


Grams. 
3,166.11 

500.00 
1,000.00 

200.00 


Grams. 

362.84 

275.80 

469.20 

93.24 


Grams. 
103.22 

45.40 
251.00 

59.14 


Grams. 

116.83 

2.05 

218 20 

34.10 


Grams. 
142.79 
228.35 


Grams. 
23.11 


1437 


Bread , 


3.85 


1438 


Meat 


28.90 


1447 


-do] 




4.90 




Total diet 










1,201.08 
53.02 


458.76 
23.65 
16.59 

435.11 
293.55 

94.85 
94.65 


371.18 
6.45 
5.80 

364.73 
247.22 

98.26 
97.09 


371.14 
22.92 


60.76 


1415 


Total feces 


73.85 


11.30 




Estimated feces from meat . 






Amount digested: 

From total diet. 




1,148.06 


348.22 


49. 46 




From meat alone 








Per cent digested : 

From total diet 




95.59 


93.82 


81.40 




From meat alone 








Experiment No. 384, subject I. 
Milk 







1 


1435 


3,382.21 
850.00 
150.00 

1,200.00 
300.00 


387.60 
468.86 
126.02 
563.04 
139.86 


110.26 

77.18 

1.19 

.301.20 
88.71 


124.80 

3.49 

124.83 

261.84 
51.15 


152.54 
388.19 


62.69 


1437 


Bread 


4.55 


1436 


Butter 


4.77 


1438 


Meat 




34.68 


1447 


.. -do 




7.35 




Total diet 










1,685.38 
52.27 


578.54 
22.05 
11.34 

556.49 
378.57 

96.19 
97.09 


566.11 
6.84 
3.99 

559.27 
309.00 

98.79 
98.73 


.540.73 
23.38 


78.04 


1442 


Total feces 


72.12 


10.26 




Estimated feci^s from meat 






Amount digested: 

From total diet 




1,633.11 


517.35 


67.78 




From meat alone 








Percent digested: 
From total diet 




96.90 


95.68 


86.87 


















g ■ : "= ■■=■ 





39 



Table 18. — Results of digestion experiments with mutton roasted — Continued. 



Lab- 
ora- 
tory 
No. 




Weight 
of mate- 
rial. 


Total 
organic 
matter. 


Protein 

(NX 
6.25). 


Fat. 


Carbohy- 
drates. 


Ash. 


1435 


Experivtent No. 385, subject 6. 
Milk 


Grams. 

3,475.27 
7.50.00 
100.00 
800.00 
400.00 


Grams. 
398.26 
413.71 
84.01 
375.36 
186.48 


Grams. 

113.29 

68.10 

.79 

200.80 

118.28' 


Grams. 

128.24 

3.08 

83.22 

174.56 

68.20 


Grams. 
156.73 
342.53 


Grams. 
25.37 


1437 


Bread 


5.77 


1436 


Butter 


3.18 


14.38 


Meat . . . 




23.12 


1447 


.do 




9.80 




Total diet 










1,457.82 
41.04 


501.26 

11.36 

1.60 

489.90 
317.48 

97.73 
99.50 


457.30 
5.29 
2.87 

452.01 
239.89 

98.84 
98.82 


499.26 
24.39 


67.24 


1446 


Total feces . 


53.29 


9.78 




Estimated feces from meat 






Amount digested: 

From total diet 




1,416.78 


474.87 


57.46 




From meat alone 








Per cent digested : 

From total diet 




97.17 


95.11 


85.45 




From meat alone. 



















EXPERIMENTS WITH PORK ROASTED. 



Four experiments, each of three clays' (9 meals) duration, were made 
Avith very fat fresh pork (hani), roasted in a gas oven until well done, 
and seasoned to taste with salt and pepper. The meat was relished 
in all the experiments. In each case bread, butter, and milk were 
eaten in addition to the meat. 

Experiment No. 386 with subject I, and No. 387 with subject B, 
began with breakfast October 22, 1902. In these experiments most 
of the visible fat was removed from the meat before it was cooked. 
Experiments Nos. 424 and 425, with subjects I and J, began with 
breakfast January 13, 1903. The ham used in these experiments was 
from a Duroc-Jersey hog about 8 months old, fattened for market on 
a ration consisting of peas, oats, and barley. The entire ham with 
the bone, but with only a part of the skin, was roasted in a gas oven 
until well done. The bone and skin were then removed. Table 19 
gives the data of these experiments. 

Table 19. — Results of digestion experiments with pork roasted. 



Lab- 
ora- 
tory 
No". 




Weight 

of mate- 

Tial. 


Total 
organic 
matter. 


Protein 
(NX 
6.25^ 


Fat. 


Carbohy- 
drates. 


Ash. 


1449 


Experiment No. 386, subject I. 
Milk 


Grams. 

4, 725. 38 
700.00 
150. 00 

1,100.00 


Grams. 
543. 42 
393. 47 
129. 26 
570. 46 


Grams. 

150. 27 

64. 05 

.83 

350.02 


Grams. 

180. 98 

2.17 

128. 43 

220. 44 


Grams. 
212. 17 
327. 25 


Grams. 
39.22 


1450 


Bread. 


4.97 


1451 


Butter 


3.16 


1452 


Meat . 


24.86 




Total diet 










1,636.61 

28.47 


56.5. 17 

12. 79 

2.73 

552,38 
347. 29 

97.74 
99.22 


532. 02 
4.39 
1.08 

527. 63 
219. 36 

99.17 
99.51 


539. 42 
11.29 


72.21 


1456 


Total feces 


39.69 


8.06 




Estunated feces from meat 






Amount digested: 

From total diet 




1,608.14 


528. 13 


64. 15 




From meat alone 








Percent digested: 

From total diet 




98.25 


97.91 


88.84 




From meat alone 



















40 



Table 19. — BenHltK of digestion experwients-with pork roasted — Continued. 



Lab- 
ora- 
tory 
No. 




Weight 
of mate- 
rial. 


Total 
organic 
matter. 


Protein 
(NX 
6.2.5). 


Fat. 


Carbohy- 
dr.ates. 


Ash. 


1449 


Experiment Xo. 387, subject B. 
Milk 


Grams. 

3,786.51 
600. 00 
100. 00 

1,000.00 


Grams. 

435. 44 

337. 26 

86.17 

518.60 


Grams. 

120. 41 

.54. 90 

.55 

318. 20 


Grams. 
145.02 

1.86 

85.62 

200. 40 


Grams. 
170, 01 
280, 50 


Grams. 
31 43 


1450 


Bread 


4,26 


1451 


Butter 


2,11 


1452 


Meat 




22,60 




Total diet 










1,377.47 
32.91 


494. 06 

10.65 

2.20 

483. 41 
316. 00 

97.84 
99.31 


432.90 
3.74 
1.25 

429.16 
199. 15 

99.11 
' 99. 38 


4.50. 51 
18.52 


60, 40 


1460 


Total feces 


44.73 


11 




Estimated feees from meat 






Amount digested: 

From total diet 




1,344,56 


431. 99 


51.29 




From meat alone 








Per cent digested: 

From total diet 




97. 01 


95.89 


84.92 




From meat alone _• . . . 








Experiment No. 424, subject I. 
Milk 










1547 


3,006.87 
.500. 00 
100. 00 

1,000.00 


343. 99 

276. 15 

88.80 

453. 70 


97.12 

41.95 

1.00 

251. 30 


116, 37 
1.15 

87.80 
202. 40 


130. 50 
233. 05 


21. 65 


1548 
1549 


Bread 

Butter 


4.00 
1.09 


1546 


Meat . . 




23.70 














1,162.64 
20.91 


391. 37 
8.60 
2.04 

•682.77 
249. 26 

97.80 
99.19 


407. 72 

3.09 

,98 

404.63 
201.42 

99.24 
99.52 


363. 55 
9.22 


50.44 


1553 


Total feces 


28.70 


5.31 




Estimated feces from meat 






Amount digested: 

From total diet 




1,141.73 


354. 33 


4.5. 13 




From meat alone. 








Per cent digested: 

From total diet 




98,20 


97.46 


89.47 




From meat alone 








Experiment No. 425, subject J. 
Milk 








1547 


3, 166. 11 
800. 00 
150.00 

1,000.00 


362. 20 
441. 84 
133. 20 
423.70 


102. 26 

67. 12 

1.50 

261. 00 


122. 53 

1.84 

1.31. 70 

162. 70 


137. 41 
372. 88 


22.80 


1548 


B read 


6.40 


1.549 


Butter 


1.64 


1560 


Meat 


32.30 




Total diet 










1,360.94 
30.52 


431.88 

13.40 

3.97 

418. 48 
257. 03 

96.90 
98,49 


418. 77 
4.05 
1.32 

414. 72 
161. 38 

99.03 
99,19 


510. 29 
13 07 


63.14 


1557 


Total feces 


43.25 


9.37 




Estimated feces from meat- 






Amount digested: 

From total diet 




1,330.42 


497, 22 


53.77 




From meat alone 








Per cent digested: 

From total diet 




97.76 


97,44 


85,16 




From meat alone 



















SUMMARY AND DISCUSSION OF RESULTS. 

In Table 20 are summarized the results of the 44 digestion experi- 
ments with a simple diet in which the amount of meat formed a large 
proportion of the total food eaten. The figures here given are the 
proportions of the different nutrients that were digested, that is, the 
coefficients of digestibility. 



41 



Table 20. — Coefficients of digestibility of nutrients of dijferent meats in experiments 

Nos. 290-301, 368-387, 419-430. 



Ex- 


Sub- 
ject. 


Kind of meat and method of cooking. 


Total diet. 


Meat alone. 


peri- 
ment 
No. 


Pro- 
tein. 


Fats. 


Car- 
bohy- 
drates. 

Per ct. 
95.5 
95.5 
96.7 
99.1 
97.7 


Ash. 


Pro- 
tein. 


Fat. 


293 


A. 

B 
D 
E 
B 

A 

B 
B 
E 
B 

A 
B 

F 
E 
B 

F 
E 
B 

F 
E 
B 

F 

E 
B 

I 
B 
B 
J 
B 
B 
J 

II 
I 
B 
H 

I 
B 

H 
I 
B 

I. 
B 

I 
J 


Lean beef round, cooked in water at 
80-85° C. fori liour » 


Per ct. 
93.0 
97.1 
98.4 
96.7 
97.2 


Per ct. 
97.8 
97.3 
98.2 
94.5 
97.6 


Per ct. 
74.2 
73.6 

86.8 
64.3 
78.4 


Per ct. 

94.1 
98.6 
98.9 
97.1 
98.3 


Per ct. 
92. 5 


294 


... .do 


9.3.1 


297 


do 


94.3 


300 


do 


O72.0 


301 


do.. 


91.0 




Average 






96.5 


97.1 


96.9 


76.5 


97.3 


92.6 




Lean Iseef round, cooked in water at 
80-85° C. for 2 hours 




290 


91.4 
96.3 
97.2 
96.6 
97.0 


97.1 
92.5 
97.7 
97.7 
97.9 


94.6 
94.4 
97.1 
98.3 
94.6 


67.5 
79.7 
80.6 
65.5 
67.1 


91.9 
97.3 
98.4 
97.4 
98.0 


89.7 


291 


do 


88.7 


292 


do 


95.5 


298 


do 


88.7 


299 


do 


89.3 




Average .... . 






95.7 


96.6 


95.8 


72.0 


96.6 


90.4 




Lean beef round, cooked in water at 
80-85° C. for 3 hours 




295 


96.9 
97.5 


99.1 
97.9 


97.6 
97.9 


83.8 
79.9 


99.7 
99.6 


99.5 


296 


do 


93.6 




Average 






97.2 


98.5 


97.7 


81.8 


99.7 


96.6 




I^ean beef round, pan broiled 




371 


96.1 
97.2 
97.4 


98.5 
98.9 
98.3 


96.0 
98.9 
95.1 


74.8 
81.1 
80.5 


96.8 
98.6 
97.9 


97.9 


372 
373 


do 

do 


99.0 
97.8 




Average 






96.9 


98.5 


96.7 


78.8 


97.8 


98.2 




Lean beef round, fried in hot lard 

do . . 




374 
375 


96.4 
95.5 
97.7 


98.7 
97.7 
98.9 


96.2 
96.6 
95.2 


75.8 
64.6 
80.0 


97.2 
95.5 
98.6 


98.3 
95.8 


376 


do 


98.9 




Average 






96.6 


98.5 


96.0 


73.5 


97.1 


97.7 




Lean beef round, roasted 




377 


98.0 
97.5 
98.7 


99.3 
98.9 
99.3 


97.2 
98.4 
96.8 


87.9 
82.0 
88.9 


99.0 
98.2 
99.7 


100.0 


378- 


do . . 


99.0 


379 


do 


99 9 




Average ... 






98.1 


99.2 


97.4 


86.3 


98.9 


99.7 




Fat beef shoulder, cooked in water at 
80- 85° C. for 2 hours 




368 


95.8 
95.9 
96.9 


98.1 
96.9 
98.0 


93.7 
98.6 
96.3 


68.6 
68.0 
85.1 


96.4 
96.2 
97.7 


97.9 


3"9 


do 


96 2 


370 


do 


97.9 










96.2 


97.7 


96.2 


73.9 


96.8 


97 3 




Beef ribs, roasted 




422 


97.0 
97.3 
98.0 
98.8 
97.1 
98.4 
96.3 


98.9 
99.1 
99.2 
99.5 
99.2 
99.6 
99.2 


95.5 
94.8 
95.0 
98.1 
95.7 
98.3 
97.0 


82.7 
78.7 
83.9 
92.7 
88.3 
93.4 
84.7 


98.9 
99.5 
99.2 
100.0 
98.3 
99.9 
97.2 


99 


423 


do 


99 


426 


do 


99 5 


427 


do 


99 9 


428 


da 


99 4 


429 


do 


100 


430 


do 


99 3 




Average 






97.5 


£9.2 


96.2 


86.3 


99.0 


99 4 




\ eal leg, roasted 




380 


96.3 
96.6 
97.7 
97.1 

98.7 
98.6 


98.9 
99.9 
99. Q 
97.7 
99.1 
98.8 


9d. 8 
97.2 
95.4 
98.4 
98.0 
97.5 


85.8 
89.0 
86.8 
80.4 
92.9 
89.3 


96.5 
97.7 
98.6 
98.0 
99.8 
100.0 


98 9 


3S2 


dj 


99 1 


383 


dD 


99 


419 


do 


91 7 


420 
421 


do 

do 


98 6 




Average 






97.5 


98.8 


97.2 


87.4 


98.4 


97 9 




Mutton leg, roasted 




381 


94.9 
96.2 
97.7 


98.3 
98.8 
98.8 


93.8 

95.7 
95.1 


81.4 
86.9 
85.5 


94.7 
97.1 
99.5 


98.0 


384 
385 


do ' '". 


98.7 
98 8 




Average 






96.3 


98.6 


94.9 


84.6 


97.1 


98 5 




Pork (fresh ham), roasted 




386 


97-7 
97.8 
97.8 
96.9 


99.2 
99.1 
99.2 
99.0 


97.9 
95.9 
97.5 
97.4 


88.8 
84.9 
89.5 
85.2 


99.2 
99.3 
9a. 2 
98. 5 


99 5 


387 


d5 


99 4 


424 


do 


99 5 


425 


do 


99 2 




Average .... 






97.6 


99.1 


97.2 


87.1 


99.1 


99 4 




.\verage for all experiments 






96.9 


98.3 


96.6 


80.7 


98.0 


97.1 



o Not included in the average. 



42 

Digestibility of total diet. — One part of Table 20 shows the coeffi- 
cients of. digestibility of the nutrients of the total diet. In the 
average of the 44 experiments 97 per cent of the total ciuantity of 
protein eaten, 98 per cent of the total fat, and 97 per cent of the 
total carbohydrates were digested. If the 23 experiments with more 
varied diet, including meat, given on pages 13 to 23, are averaged, 
the coefficients for fat and car})ohydrates are identical with these 
just given, but that for protein is 93 per cent. The reason for this 
lower figure for protein in the more varied diets is that the latter 
contains relatively large proportions of vegetable foods, in which the 
protein is not so thoroughly digested as in meat, which formed so 
much larger proportion of the total food in the more simple diets. 
In the average of upward of 400 experiments ^\^th various kinds of 
mixed diets made in connection with the nutrition investigations of 
this Department the coefficients of digestibility of the nutrients were 
found to be protein 92, fat 95, and carbohydrates 97 per cent. It 
is apparent, therefore, that the nutrients in the simple diet used in the 
experiments here summarized were thoroughly digested. 

The minor averages in Table 20, i. e., the averages of the results 
of similar experiments, agree favorably with the general average. 
Thus the coefficients for protein range in the various averages from 
96 to 98 per cent, those for fat from 97 to 99 per cent, and those for 
carbohydrates from 95 to 98 per cent. It is also noticeable that the 
results for different subjects in similar experiments agree, in almost 
every case, about as closely as can be expected in investigations of 
this nature. There are, in fact, only three noteworthy exceptions. 
In the experiments with lean beef cooked in water one hour, one 
subject digested 93 per cent of the protein, whereas the other four 
subjects digested 97 to 98 per cent. In the experiments with lean 
beef cooked in water two hours, one subject digested 91 per cent of 
the protein as compared with 96 to 97 for the other four subjects, 
and one subject digested 93 per cent of the fat, whereas each of the 
other four subjects digested 97 per cent. In all of the other experi- 
ments the agreement in results for all the different subjects on the 
same diet was satisfactorily close. 

It would appear from these data that differences in the method of 
cooking the meat had little influence upon the digestibility of the 
nutrients of the total diet. For example, lean beef round was cooked 
in six different ways, and in these experiments the coefficients for 
protein in the total diet range, in the averages, from 96 to 98 per 
cent, those for fat from 97 to 99 per cent, and those for carbohydrates 
from 96 to 98 per cent. 

It is also noticeable that there is not any practical difference in 
digestibility of the diets with diflerent kinds of meat similarly cooked. 
Thus the average for the total diet in experiments with fat beef 



43 

shoulder cojked in water agrees closely with that for lean beef round 
similarly cooked; and in the experiments ^\dth lean beef round, beef 
ribs, veal, mutton, and pork, all roasted, the average coefficients 
range for protein from 95 to 97 per cent. These variations are 
smaller than some of those between the results for different indi- 
viduals wdth the same kind of meat. 

In brief, then, whether individual experiments or average figures 
be considered, differences in either the kind of meat or in the method 
of cooking the meat apparently had no decided effect upon the diges- 
tibiUty of the nutrients of the total diet used in these experiments. 

Digestihility of the meat alone. — The data in the last two columns of 
Table 20 show the coefficients of digestibility of the protein and the fat 
of the meat alone as distinguished from those for the corresponding 
nutrients in the total diet. These values were computed, in the man- 
ner described on page 26, from the data for total diet as directly deter- 
mined b}^ the experiments, by assuming certain factors for the digesti- 
bility of the nutrients of the foods eaten with meat. These factors are 
based upon the results of digestion experiments w4th such food mate- 
riids. It is, of course, not impossible that some error is involved in 
their iise in the present experiments, but whatever error there may be 
is believed to be small, and the computed coefficients of digestibilit)^ of 
the protein and fat of the meat alone are believed to be approximately 
correct. At any rate, since the same factors are applied to all experi- 
ments alike, the results computed by use of them are just as compara- 
ble wiih. each other as those determined for the total diet directly from 
the experimental data. It is possible, therefore, to judge from the 
figures in the table what was the effect of the different methods of cook- 
ing upon the digestibility of the nutrients of the meat alone. 

As regards protein, no effect seems to be indicated. The range in 
coefficients for the minor averages is from 97 to 100 per cent, and the 
average for all 44 experiments is 98 per cent. The agreement between 
results for individual subjects in similar experiments was correspond- 
ingly close in nearly every case, the chief exception being the results 
with subject A in the experiments with lean beef cooked in water for 
one and for two hours ; but in both of these sets of experiments the 
results with the other subjects agree closel}^ with each other. 

Considermg all the figures, both those for different subjects in sim- 
ilar experiments and the averages for the different kinds of experi- 
ments, the indications are that the protein of the meat was quite thor- 
oughh' digested, whether the same kind of meat was cooked in differ- 
ent ways or different kinds of meat were similarly cooked. The varia- 
tions for the different experiments are too small and too irregular to 
indicate any effect upon digestibilit}^ that may be ascribed to differ- 
ences in the kinds of meat used or in the methods of cooking. 

The same is true as regards fat, except in the case of lean beef cooked 



44 

in water. If these experiments be disregarded, the computed coeffi- 
cients for fat agree very favorably with each other in the minor aver- 
ages, the range being also from 97 to 100 per cent, and the general 
average for these 32 experiments being 99 per cent. The results with 
the different subjects in similar experiments also agree closely with 
each other with one exception — the coefficient for one subject with 
roast veal being 92 per cent, whereas those for the other five sub- 
jects ranged from 99 to 100 per cent. 

In the experiments with lean beef cooked in water, the calculated 
coefficients for fat are decidedly low, both in the case of meat cooked 
for one hour and in that of meat cooked for two hours. The average 
for the meat cooked for three hours is better, but there were only two 
of these experiments, in one of which the coefficient is high, and this 
raised the average figure. In the other of these two experiments, the 
coefficient is like those for meat cooked one hour. 

These low figures would at first appear to indicate that the fat of 
meat cooked in water was less thoroughly digested than that of meat 
otherwise cooked, but it is believed that such conclusions should not 
be drawn from these data. The low coefficients are more probably to 
be ascribed to slight inaccuracy in the assumed factors for digestibility 
of the fat of the foods other than meat. The quantity of fat in the 
meat in these particular experiments forms only a small proportion of 
the total fat of the diet, and where such is the case slight variations in 
the assumed factor for the fat of the other foods make relatively large 
difi^erences in the computed coefficients for the fat of the meat. It is 
very probable that if the proportion of fat in the meat used in these 
12 experiments had been larger the coefficients would have been more 
like those for the meat used in the other experiments. This is indi- 
cated by the fact that in the 3 experiments with fat beef shoulder 
cooked in water two hours, in which the meat supplied a larger part of 
the fat of the diet, the coefficients for fat agree with those for meat 
otherwise cooked, and also by the fact that the fat of the total diet — 
that is, fat froiii all the food materials including the meat — was as 
thoroughly digested in these experiments as in the others. There 
seems, therefore, no reason for believing that the fat of the meat alone 
was any less thoroughly digested m these than in the other experi- 
ments. 

Considering all the experiments, it seems fair to assume from the 
data here summarized that about 98 per cent of the protein and 98 
per cent of the fat of the meat were digested, and inasmuch as the 
simple diet used in these experiments was, as a whole, at least as 
thoroughly digested as the ordinary mixed diet, these data may be 
considered as representing the digestibility of the nutrients of meat 
eaten in combination with other common food materials. 



45 

Poda and Praiisnitz* studied the digestibility of roasted beef in a 
comparatively simple diet, and by making allowance for the digesti- 
bility of the additional food materials in the diet as previously esti- 
mated, they computed the digestibility of tiie meat itself. They 
found that 99 per cent of the protein of the meat was digested, which 
agrees with the figure given above for the average of the experiments 
here reported. Other investigators have reported experiments in 
which the diet included meat together with other food materials — for 
example, bread, which was the special object of study — and it would 
apparently be possible from the results of these to estimate the digesti- 
bility of the meat alone. A cursory examination of the results of 
some of these experiments indicates that the estimated digestibility of 
the meat would correspond with that obtained in the experiments 
here considered. But inasmuch as such estimates were not pre- 
viously reported by the investigators themselves, the work has not 
been summarized in the present publication for comparison. 

The investigation by Forster, mentioned on page 6, is of interest 
here, as the object was, like that of the experiments reported in the 
present bulletin, to determine the digestibility of meat cooked in 
different ways. He made 33 experiments in 7 series, in which dif- 
ferent cuts of beef were prepared as follows: (1) Raw, chopped, and 
flavored with salt, pepper, and onion; (2) cooked in butter, i. e., cut 
in slices 1 to 1.5 centimeters thick, sprinkled with s'alt and pepper, 
pounded, and fried for three to five minutes in a pan containing 
sufficient melted butter to cover the meat. Meat thus prepared was 
considered the most palatable of any used; (3) cut as in 2, and broiled 
(or roasted) for four minutes, with frequent turning in a closed, gas- 
heated grilling apparatus; (4) placed w^ith flavoring matters in cold 
water and boiled for one and one-half to two hours; (5) same as 4, 
save that the water at the start was at the boiling point; (6) soaked 
for two weeks in brine, removed twenty-four hours before use, soaked 
in water, and boiled; (7) salted as in 6, then smoked for three days, 
soaked in water, and boiled. In four series of experiments two cuts 
from the same animal were used, a cheaper one from the hind shank 
and a more expensive one from the shoulder. For the roasted meat 
only that from the shank was used,. and for the salted and smoked 
meats only the shoulder. 

The solid food consisted entirely of the meat, but beer or wine, to 
which all the subjects were accustomed, was allowed at meals. Two 
or more subjects were employed in each series, the author himself 
serving in all of them. The food and feces were weighed and anatyzed 
in the usual manner. The results obtained in these experiments are 
summarized by averages in Table 2 1 . 



ffZtschr, Biol., 42 (1901), p. 377. 



46 



Table 21. — Results of digestion experiments with meat alone. 



Kind of meat. 


Coefflcients of di- 
gestibility. 


Kind of meat. 


Coefflcients of di- 
gestibility. 




Protein. 


Fat. 


Protein. 


Fat. 


Hind quarter, raw, average of 
5 experiments 


Per cent. 
95.23 

96.70 

96.32 

97.71 

95.46 


Per cent. 
83.58 

87.33 

95.19 

98.62 

88.70 


Shoulder, boiled, average of 
4 experiments 


Per cent. 
96.40 

96.54 

96.81 

97.35 


Per cent. 
81.09 


Shoulder, raw, average of 7 
experiments 


Hind quarter, boiled, aver- 
age of 3 experiments 

Shoulder, pickled, average of 
3 experiments 


51.82 


Hind quarter, fried in butter, 
average r f 2 experiments . . . 


94.82 


Shoulder, fried in butter, aver- 
age of 2 experiments 


Shoulder, salted and smoked, 
average of 3 experiments. . . 


86.82 


Hind quarter, broiled, aver- 
age of 4 experiments 





In these experiments the digestibiUty of the protein of the meat 
was m all cases quite thorough, and the results for the different sub- 
jects agree fairly well with each other. The averages for the experi- 
ments with meat cooked in different waj's range from 95 per cent 
with broiled meat to 98 per cent with meat fried in butter. In the 
average of all 33 experiments the digestibility of the protein was 90 
per cent. This is a trifle lower than the average for the digestibility 
of protein of meat alone in Table 21 abov;e, but the difference is in- 
significant. The lower average in Forster's experiments is possibly 
due partly to the fact that meat formed the total food material, 
whereas in the experiments here reported meat was eaten in combi- 
nation with other common food materials. It has been commonly 
observed, as already explained, that a given food material may be 
more thoroughly digested when it is eaten with other food materials 
than when eaten alone. In view of this fact the figure for digesti- 
bility of protein obtained in the experiments here reported is believed 
to be supported by the results obtained by Forster in experiments 
such as his. Furthermore, the agreement in the results with meat 
cooked in different ways shows that the differences in the method of 
cooking had no effect upon the digestibility of the protein of the meat, 
which also supports the deduction drawn from the experiments 
reported in the present bulletin. 

As regards the digestibility of fat, most of the results obtained by 
Forster were noticeably lower than those found in the present experi- 
ments. In 3 cases among the average figures given in the table above 
the digestibility of fat ranged from 95 to 99 per cent, but in 5 cases the 
coefficients ranged from 81 to 89 per cent; and in 1 case it is as low 
as 52 per cent. These variations are so wide that the results are 
hardly to be considered in drawing deductions regarding the digesti- 
bility of the fat of meat cooked in different waj's. 



47 

DIGESTIBILITY OF THE NITROGEN (PROTEIN) AS CORRECTED 
FOR METABOLIC PRODUCTS IN THE FECES. 

The values for digestibility considered in the preceding discussion 
are those determined according to the usual custom, by analyzing 
the food and the corresponding feces in the same manner and deduct- 
ing the ingredients of the latter from those of the former. It is under- 
stood that this represents apparent rather than actual digestibility, 
because, as has been frequently pointed out, the feces do not consist 
entirely of undigested food. In fact they are composed in large part 
of the so-called metabolic products, which consist of residues from 
the digestive juices, epithelial debris from the nmcous lining of the 
intestines, etc. Some of these products contain nitrogen, which is of 
course included with that from the undigested food in the total nitro- 
gen of the feces as ordinarily determined ; and they also contain sub- 
stances that are soluble in ether and are extracted along with the 
undigested fat. To determine the actual digestibility of food it would 
therefore be necessary to separate the ingredients of the metabolic 
products from those of the undigested food. 

Various methods for making such separation, and thus affording 
means for determining the ingredients of undigested food, have been 
tried by different investigators, but no attempt has been made to 
summarize them here. It will suffice to say that none of the methods 
thus far proposed has proved entirely satisfactory. In connection 
with the digestion experiments with meat in a very simple diet 
reported in this bulletin, however, an effort was made to get some 
light upon the actual digestibility of the protein of the meat by follow- 
ing one of the common methods of removing metabolic nitrogen from 
the feces. This consists of digesting the feces with an acid-pepsin 
solution, on the assumption that this will dissolve the metabolic 
products containing nitrogen but will not affect to any appreciable 
extent the nitrogenous substances of the food that were not digested 
in the alimentary tract. 

The digestive solution used contained 1.25 grams of pepsin per liter 
of 0.33 per cent hydrochloric acid. The weighed sample of feces was 
placed in a flask with 100 cubic centimeters o^ this solution and kept 
for twenty-four hours at 38° to 40° C. The material in the flask was 
then filtered, and the residue was thoroughly washed and dried upon 
the filter paper. The top of the paper was then cut oft' to get rid of 
any soluble material dried there and the remainder containing the 
undissolved residue was dropped into a Kjeldahl flask and the nitrogen 
was then determined in the usual manner. 

The nitrogen in the material not dissolved by the pepsin solution 
was considered as pertaining to the protein of the food that escaped 
digestion, and the actual digestibility of the nitrogen was computed 

466.3— Bull. 193—07 4 



48 



from the amount consumed in the food, and that thus determined for 
undigested material. These figures are summarized in Table 22. 
The coefficients thus obtained for digestibility of nitrogen are of 
course practically the same as for protein, since this is the onh' source 
of nitrogen in the food. 

In addition to the data for total diet, the actual digestibility of the 
protein of the meat alone has also been estimated. This was done by 
assuming that 2 per cent of the nitrogen of the milk and 5 per cent of 
that of the bread eaten with the meat would be accounted for in the 
undigested food residue. This factor for bread nitrogen was derived 
from the results of digestion experiments with bread by Woods," in 
which he computed the actual digestibility of the bread protein 
according to the same method as here followed for the meat. 

Table 22. — Metabolic nitrogen in feces as determined by treatment with pepsin solution, 
experiments Nos. 290-301, 368-387, 419-430. 



Ex- 
peri- 
ment 

No. 


Sub- 
ject. 


Kind of food. 


Nitro- 
gen in 
food. 


Air- 
dried, 
feces.' 


Nitrogen in 
total feces. 


Nitrogen in 
feces undis- 
solved by pep- 
sin solution. 


Nitrogen di- 
gested. 


290 


A 
B 
B 
A 
B 
A 

B 

D 

E 

B 

E 
B 

E 

E 
B 


Beef, bread, butter: 
Entire diet 


Grams. 
3t).09 
28.95 

48.44 
38.73 

46.75 
40.32 

34.51 
26.92 

38.55 
32.24 

25.83 
16.42 

33.24 
21.70 

60.57 
43.90 

85.68 
51.66 

61.86 
44.28 

76.54 
50.48 

64.92 
46.09 

70.47 
50.05 

72.85 
50.65 

64.31 
54.27 


Grams. 
43.38 


Per ct. 
6.32 


Gi^ms. 
3.03 
2.02 

1.68 

.74 

1.30 
.36 

3.03 
1.30 

1.13 
.20 

.82 


Per ct. 

2.88 

2.39 
2.14 
2.71 
2.22 

2.14 


Grams. 
1.39 
1.03 

.92 
..52 

.51 
.13 

1.05 
.66 

.60 

.27 

.38 


Grams. 
34.70 
27.92 

47.52 
38.21 

46.24 
40.19 

33.46 
26.26 

37.95 
31.97 

25.45 
16.42 

32.87 
21.70 

60.22 
43.90 

84.79 
51.66 

61.01 
44.02 

75.83 
50.48 

64.34 
46.09 

64.41 
50.26 

72.02 
50.49 

63.74 
54.08 


Per ct. 
96.07 
96.44 


291 


Beef, bread, milk: 

Entire diet 

Meat alone 

Beef, bread, butter: 

Entire diet 

Meat alone 

Beef, bread, butter: 

Entire diet 

Meat alone 

Beef, bread, butter: 

Entire diet 

Meat alone 

Beef, bread, butter, 
milk: 

Entire diet 

Meat alone. . . .' 

Beef, bread, butter, 
milk: 

Entire diet 

Meat alone 

Beef, bread, butter, 
milk: 

Entire diet 

Meat alone 

Beef, bread, butter, 
milk: 

Entire diet 

Meat alone 

Beef, bread, butter, 
milk: 

Entire diet 

Meat alone 

Beef, bread, inilk: 

Entire diet 

Meat alone 

Beef, broad, butter, 
milk: 

Entire diet 


.38.29 


4.49 


98.10 
98.66 


292 


23.98 


5.44 


98.90 
99.67 


293 


38.75 


6.21 


96.96 
97.55 


294 


27.10 


4.17 


98.44 
99.16 


295 


18.04 


4.52 


98.53 
100.00 


206 


18.85 


4.41 


.83 


2.01 


.38 


98.89 
100.00 


297 


21.50 


4.39 


.94 
.46 

2.90 
.99 

1.87 
..54 

2.51 
1.24 

1.79 
.76 

2.98 
1.52 

2.98 
1.64 

1.96 
1.05 


1.63 


.35 


99.42 
100.00 


298 


62.05 


4.68 


1.43 


.89 


98.96 
100.00 


299 


52.00 


3.60 


1.63 
1.27 


.85 
.26 

.71 


98. 63 
99.41 


;io() 


.55.60 


4.51 


99.07 
100.00 


301 


37.01 


4.77 


l.,54 


.58 


99.11 
100.00 


368 


Beef, bread, butter, 
milk: 

Entire diet 

Meat alone 

Beef, bread, milk: 

Entire diet 

Moat alone 

Beef, bread, milk: 

Entire diet 

Meat alone 


75 . 76 


3.94 


1.40 
1.24 
1.41 


1.06 
.39 

.83 
.16 

.57 
.19 


98.50 
99.23 


3(19 


67.32 


4.43 


98.66 
99.68 


370 


40.76 


4.82 


99.11 
99.66 



aJJ. S. Dept. Agr., Office of Experiment Stations Buls. 85 and 143. 



49 



Table 22. — Metabolic nitrogen in feces as determined by treatment with pepsin solution, 
experiments Nos. 290-301, 368-387, -^/S-^-SO— Continued. 



371 



Ex- 

p:ri- I Sub- 
mcnt ject. 

No. 



E 



E 



H 



H 



B 



H 



B 



B 



Kind of food. 



Nitro- . 
gen in 
food. 



Beef, bread, butter, 
inilk: 

Entire diet 

Meat alone 

Beef, bread, milk: 

Entire diet 

Meat alone 

Beef, Ijread, milk: 

Entire diet 

Meat alone 

Beef, bread, butter, 
milk: 

Entire diet 

Meat alone 

Beef, bread, milk: 

Entire diet 

Meat alone 

Beef, bread, milk: 

Entire diet 

Meat alone 

Beef, bread, butter, 
milk: 

Entire diet 

Meat alone 

Beef, bread, milk: 

Entire diet 

Meat alone 

Beef, bread, milk: 

Entire diet 

Meat alone 

Veal, bread, milk: 

Entire diet 

Meat alone 

Mutton, bread, milk: 

Entire diet 

Meat alone 

Veal, bread, butter, 
milk: 

Entire diet 

Meat alone 

Veal, bread, butter, 
milk: 

Entire diet 

Meat alone 

Mutton, bread, butter, 
milk: 

Entire diet 

Meat alone 

Mutton, bread, butter, 
milk: 

Entire diet 

Meat alone 

Pork, bread, butter, 
milk: 

Entire diet 

Meat alone 

Pork, bread, butter, 
milk: 

Entire diet 

Meat alone 

Veal, bread, milk: 

Entire diet 

Meat alone 

Veal, bread, butter, 
milk: 

Entire diet 

Meat alone 

Veal, bread, butter, 
milk: 

Entire diet 

Meat alone 

Beef ribs, bread, but- 
ter, milk: 

Entire diet 

Meat alone 

Beef ribs, bread, but- 
ter, milk: 

Entire diet 

Meat alone 



Air- 
dried 
faces. 



Grains. Grams. 

7:3.91 I .59.83 
50.09 



82.11 
.54.6.5 



40.52 



70.56 42.18 
54.65 



Nitrogen in 
total feces. 



Per ct. 

4.80 



69.27- 
43.48 

71.60 
48.92 

61.93 
38.05 



81.47 
,57.16 

70.20 
47.63 

77.42 
57.10 

79.52 
58.50 

73.40 
49.62 



101.18 
71.99 



69.39 
53. 99 



92.57 
62. 38 



80.20 
51.05 



90.43 
56.01 



79.05 
50.91 

72.17 
45.41 



79.05 
49.95 



67. 36 
45.41 



67.47 
35. 27 



54.26 



65.63 
42.21 



;i5.01 

:i5.04 
27.78 
45.56 
73.85 



56.00 



34.42 



72.12 



53.29 



39.69 



44.73 



39.79 



25.73 



26.87 



59.48 



65.45 I 60.97 
35.27 



5.59 
4.39 

4.56 
4.86 



3.36 



4.56 
4.94 



Grams 
2.87 
1.23 

2.27 
.36 

1.85 
.95 



2.47 

.88 

3.19 
1.96 



Nitrog'n in 
feces undis- 
solved by pep- 
sin solution. 



Per ct. 

2.18 



1.&3 



2.00 



3.64 

6.47 



5.12 



6.10 



4.61 



4.89 



3.41 



5.16 



3.81 



5.35 



3.99 



3.52 



3.40 



1.42 
.36 



1.59 
.32 

1.73 
.69 

1.01 
.02 

2.95 
1.87 

3.78 
2.36 



3.42 
1.14 



1.59 
.53 



3.53 
1.32 



1.82 



1.94 

1.77 
1.54 



2.09 
1.63 
1.32 
2.05 
1..54 



Grams. 

1.30 

.53 

.74 



2.29 



1.93 



1.47 



2.05 
.03 



1.70 



2.13 
.60 



1.03 



.94 



2.02 



2.90 



1.77 



1.44 



1.75 



1.42 
1.26 



1.14 



1.28 



.94 



.84 
.38 



1.05 
.27 

1.16 
.51 

.65 
.03 



.73 
.05 

.57 
.37 



.94 
.35 

1.14 
.42 



1.28 
.28 



.66 
.17 



1.06 
.05 



.77 



.69 



.64 
.50 



.29 



.34 



.53 



.57 



Nitrogen di- 
gested. 



Grams. 

72. (.1 
49.56 

81.37 
54.65 

09.72 
54.27 



68.22 
43.21 

70.44 
48.41 

■61.28 
38.02 



80.74 
57.11 

69.63 
47.63 

77.05 
57.16 

78.58 
58.15 

72.26 
49.20 



99.90 
71.71 



68.73 
53.82 



91.53 
62.33 



79.43 
51.05 



89.74 
56.01 



78.41 
50.91 

71.67 
45.41 



78.76 
49.95 



67.02 
45.41 



66.94 
35.27 



64.88 
35.27 



Perct. 

98.24 
98.24 

99.10 
100.00 

98.81 
99.30 



98.48 
99.38 

98.38 
98.99 

98.95 
99.92 



99.10 
99.91 

99.19 
100.00 

99.52 
100.00 

98. S2 
99.40 

98.45 
99.15 



98.74 
99.61 



99.05 
99.69 



98.86 
99. 92 



99. 04 
100.00 



99. 24 
100. 00 



99. 19 
100. 00 

99. 31 
100. 00 



99.63 
100. 00 



99.50 
100. 00 



99.21 
100. 00 



99.13 
100.00 



50 

Table 22. — Metabolic nitroyeii in feces as determined by treatment with pepsin soluHon, 
experiments Nns. JDO-SOl. 368-387, ilH- 



Ex- 
peri- 
ment 

No. 


Sub- 
ject. 


424 


I 


425 


J 


426 


B 


427 


J 


428 


1 


429 


B 


430 


J 



Kind of I'oQil. 



Ham, bread, butter, 
milk; 

Entire diet 

Meat alone 

Ham, lircad, butter, 
milk: 

Entire diet 

Meat alone 

Beef ribs, bread, but- 
ter, milk: 

Entire diet 

Meat alone 

Beef ribs, bread, but- 
ter, milk: 

Entire diet 

Meat alone 

Beef ril).9, bread, Init- 
ter, milk: 

Entire diet 

Meat alone 

Beef rilis, bread, but- 
ter, milk: 

Entire diet 

Meat alone 

Beef ril)s. bread. Ijut- 
ter, milk: 

Entire diet 

Meat alone 



Nitro- 
gen in 
food. 



Gram.i. 
(32. (12 
40.21 



69.10 
41. 70 



72. 36 
43. 36 



84.85 
59.14 



54.73 
36. 19 



67.98 
41.59 



85.16 
60.49 



Air- 
dried 
feces. 



Grams. 
28. 70 



Nitrogen in 
total feces. 



Per cl. 
4.79 



43. 25 



51.62 



25. 62 



38.30 



23.35 



56.18 



4.96 



2.85 



Nitrogen in 
feces undis- 
solved by pep- 
sin solution. 



Grams. Per ct. 

1.38 i 1.71 

.06 I 



2.14 
.21 

1.46 



3.09 



4.20 



4.74 



5.64 



1.02 



1.61 
.37 



1.11 



:117 
Iv25 



Grams. 
a 49 



1.04 



1.39 



1.27 



2.35 



1.62 



.45 



.50 



.36 



.49 



.55 



.91 
.06 



Nitrogen di- 
gested. 



Grams.'' Per cl. 
62. 13 j 99. 22 

40.21 ' inn.no 



68.65 : 99.35 
41.76 j 100.00 



71. 86 ; 99. 31 
43.36 100.00 



84.49 I 99.58 
59.14 I 100.00 



54.24 
36.19 



67.43 
41.59 



84.25 
60.43 



99. 10 
1(K). 00 



99. 19 
100. 00 



98.93 
99.90 



The above data are summarized in Table 23, the results for similar 
experiments being brought together and averaged. 

Tablk 23. — Coefficients of digestibility of protein after correction for metabolic products. 



Ex- 




peri- 


Sub- 


ment 


ject. 


No. 




293 


A 


294 


B 


297 


D 


300 


E 


301 


B 


290 


A 


291 


B 


292 


B 


298 


E 


299 


B 


295 


A 


296 


B ' 



371 


F 


372 


E 


373 


B 


374 


F 


375 


E 


376 


B 



Kind (if moat. 



Lean beef round, cooked in waterat 80° to 85° C. for 1 hour. 

....do 

....do 

....do 

....do 



Average 



Lean beef round, cooked in water at 80° to 85° C. for 2 hours. 

....do 

....do 

....do 

....do 



Average 



Lean beef round, cooked in water at 80° to 85° C. for 3 hour^ 
....do 



.\verage. 



Lean beef round jian broiled 

....do 

....do 

Average 



Lean beef round fried in hot lard 

do 

do 



Average . 



Protein digested in- 



Total food. Meat alone. 



Per cent. 
96. 96 
98.44 
99.42 
99.07 
99.11 



98.60 



96.07 
98.10 
98.90 
98.96 
98.63 



Per cent. 

97.55 

99. 16 

100.00 

100. 0(J 

100. 00 



99.34 



96.44 
98. 66 
99.67 
100.00 
99.41 



98.13 


98.84 


98.53 
98.89 


100.00 
100.00 


98.66 


100.00 


98.24 
99.10 
98.81 


98.24 

100.00 

99.30 


98.72 


99.18 


98.48 
98.38 
98.95 


99.38 
98.96 
99.92 


98.60 


99.42 



51 



Table 23. 



-Coefficients of digestibility of protein after correction for iiietaholir products- 

Continued. 



Ex- 


Sub- 
ject. 


Kind of meat. 


Protein digested in- 


peri- 
ment 
No. 


Total food. 


Meat alone. 


377 
378 


F 
E 
B 

F 
E 
B 

I 
B 
B 
J 
B 
B 
J 

n 

I 

B 
II 
I 
B 

H 
I 
B 

I 
B 
I 
J 


Lean beef round roti sted 

do 


Per cent. 
99.10 
99.19 


Per cent. 
99. 91 
inn.no 


379 


do 


99. 52 100. 00 




Average 






99.27 


99.97 




Fat beef shoulder cooked in water at 80° to 85° C. for 2 hours 

do 




3t)8 
359 


98. .50 
98.86 
99.11 


99.23 
99. 68 


370 


do . . 


99.65 




Average 






98.82 


99.52 




Beef ribs roasted 




422 


99.21 
99.13 
99.31 
99.58 
99.10 
99.19 
98.93 


100. 00 


423 


do 


100. 00 


42(; 


do . . . 


100. 00 


427 


. .do 


100. 00 


428 


do 


100. 00 


429 


do 


100. 00 


4.30 


. ..do 


99. 90 










99.20 


99. 99 




Veal leg roasted 

do 




380 
382 


98.82 
98.74 
99.05 
99.31 
99.03 
99.50 


99.40 
99.61 


383 


do 


99. 69 


419 


do ... 


100. 00 


420 


..do 


100. 00 


421 


do 


100. 00 




Average 






99.18 


99. 7S 




Mutton leg roasted . .... 




381 


98. 45 99. 15 


384 


.. ..do 


98.86 ' 99.92 


385 


do 


99.04 


100. 00 




Average 






98.78 


99.69 




Pork, fresh ham, roasted 

do 




386 
387 


99.24 
99.19 
99.22 
99.35 


100. 00 
100. 00 


424 


do 


100. 00 


425 


do ... 


100. 00 




Average .* 






99.25 


100. 00 



The actual digestibility of the protein of the total diet and of the 
meat alone, as shown by the figures in Table 23, is high. The figures 
for meat alone would indicate that practically all of the protein of 
the meat was digested. This is not at all improbable, though it 
should be stated that severe criticism of the method by which the 
data were derived would suggest that such a conclusion can not be 
drawn without some qualification. It is not certain that the pepsin 
solution, even though very weak, would digest only the nitrogenous 
materials from the metabolic products of the feces, and leave all of 
the undigested food protein unaffected; possibly some of the latter 
might be dissolved also. Furthermore, it is possible that the undi- 
gested meat protein would be more affected than that from bread, as 
experiments indicate that artificial digestive solutions act more 
readily upon the former than upon the latter. Nevertheless, the 
authors are inclined to believe, in the light of results obtained in 
artificial digestion of meat, that the results shown in Table 23 are 
not far from the truth, and that the actual digestibility of meat pro- 
tein is near 100 per cent. 



52 



INCOME AND OUTGO OF NITROGEN AND GAIN OR LOSS OF 

PROTEIN. 

In each digestion experiment tlie urine of the subject was collected 
for each twenty-four hours, and the quantity of nitrogen in it deter- 
mined b}' the Kjeldahl method. At a certain hour on the first day 
of each experiment the urine was voided and rejected, then all that 
was eliminated up to the same hour the next day was collected for 
the day's output. In most of the experiments the urine periods 
began at 7 a. m., but in experiments Nos. 275 to 282 they began 
at 1 p. m. In each case the final period ended at the corresponding 
hour on the first day following the experiment. In experiments Nos. 
284 to 289 the urine was collected in six-hour periods, and the nitrogen 
in it determined for each period. 

The urine data for the different exoeriments are o-iven in Table 24, 
showing the total weight of urine for each day and the percentage 
and amount of nitrogen in it, except that in experiments Nos. 284 
to 289, in which the determinations were made in six-hour periods, 
the percentage of nitrogen in the daily urine is not given, the total 
weight of urine and quantity of nitrogen for the day being the sums 
of the corresponding data for the six-hour periods. The table also 
shows the total quantity of nitrogen in the urine, in the feces, and 
in the food for each experimental period, and the apparent gain or 
loss of nitrogen and protein by the body, the protein being computed 
from the estimated gain or loss of nitrogen in the usual manner, by 
multiplying by the factor 6.25. 

Table 24. — Quantity and. nitrogen content of urine per day, total income and outgo oj 
nitrogen, and apparent gain or loss of protein, in experiments Nos. 267-301, 368-8^7^ 
419-429. 





■4-J 

8 

3 

cc 
A 

B 
A 


Kind of food. 


oB 
=» S 
^^ 
ft 

f 1 

^4 


Weight 
urine. 


Quantity of 
nitrogen in 


Total quantity of 
nitrogen in— 


Apparent gain 

(+) or loss {—■■ 

to body. 


dail.y urine. 


Urine. 


Feces. 


Food. 


Nitro- 
gen. 


Pro- 
tein. 




Mixed diet, including 
lean heef pan l)roiled. 


Grams. 
871.1 
693.5 
713.8 
688.6 


Pr. ct. Grams. 
1.43 1 12.46 


Grams. 


Grams. 


Grams. 


Grams. 


Grams. 


267 


1.69 
1.67 
1.62 


11.72 
11.92 
11. .32 






































i 
Total •••• 

Mixed diet, including ., 
lean beef pan l)roiled. •' X 

4 
Tolal 
















2,977.0 




47.42 


3.92 


47.80 


-3.54 


—22.13 




645.0 
8.30.3 
831.1 
862.2 


1.94 12.51 
l.Gl 13. 4G 
l.CO 1 13.80 
1.62 ! 13.97 












268 


























* 
























2,594.1 


1 


53.74 


4.36 


63.84 


+ 5.75 


+ 35.95 












269 


Mixed diet, including ( 1 
lean beef pan broiled. < 2 


648.9 
768.3 
769.5 


1.53 1 9.93 
1.40 1 10.76 
1.33 10.34 


























Total 


l3 


























2,186.7 


1 


31.03 


2.82 


34.50 


+ .74 


+ 4.63 













53 



Table 2i.— Quantity and nitrogen content of urine per day, total income and outgo of 
nitrogen, and apparent gain or loss of protein, cfc— Continued. ' ' 



1^ 


' 1 

3 

B 

A 

B 
A 

B 

B 

B 

3 

B 

B 
B 


Kind of food. 


E 

03 P 
P 

1 3 


Weight 

of 
urine. 


Quantity of 
nitrogen in 
daily urine. 


Total quantity of 
nitrogen in— 


Appar nt gain 

( + ) orloss(-) 

to body. 


a. 


Urine. 


Feces. Food. 


Nitro- 
gen. 


Pro- 
tein. 


270 


Mixed diet, including 
lean beef pan broiled 

Total 


Grams. 
748.4 
666.. 5 
835.2 


Pr.ct 
1.70 

1.58 
1.71 


Grams 
12.72 
10.53 
14.28 


Grams 


Grams. 1 Grams 

1 1 . 


Grams 


Grams. 










1 






























2,250.1 






37.53 


3.09 


47.77 


+ 7.15 


+ 44.69 




Mixed diet, including 
lean beef cooked in 
water '^ hnni*^ 


f 1 
J 2 
1 3 
I 4 






271 


644.1 
916.2 
680.8 
793.2 

3.034.3 


1.33 
1.15 
1.60 
1.46 


8.57 
10.54 
10.89 
11.58 


• 






















Total 










































41.58 


3.96 


51.59 


+6.05 


+37.81 




Mixed diet, including 
lean beef cooked in 
water 2 hours 

Total 


f 1 

2 

1 3 
I 4 








272 


735.9 
739.3 
726.8 
917.1 


1.22 
1.46 
1.61 

1.57 


8.98 
10. V9 
11.70 
14.40 


















































3,119.1 






45.87 


2.96 


66.48 


+ 17.55 


+ 110.32 




Mixed diet, including 
lean beef cooked in 
water 4 hours 

Total 


1 
J 2 
1 3 
I 4 






2;3 


809.4 
693.0 
630.3 
747.4 


1.23 
1.55 
1.66 
1.54 


9.97 
10.74 
10.46 
11.51 



















































2,880.1 






42.68 


2.eo 


49.31 


+ 4.03 







Mixed diet, including 
lean beef cooked in 
water 4 hours 

Total 


1^ 

I 4 






+ 25.19 


2;4 


804.2 
805.4 
803.5 
755.0 


1.38 
1.47 
1.62 
1.89 


11.10 
11.84 
13.02 
14.27 


















































3, 168. 1 






50.23 


2.55 


64.46 


+ 11.68 






Mixed diet, including 
lean beef cooked in 
water 2 hours 

Total 


f 1 
2 

3 

, 4 






+ 73.01 


2io 


1,203.6 

821.3 

1,219.8 

1,149.7 


1.29 
1.93 
1.48 
1.22 


15.53 

15.85 
18.05 
14.03 




































4, .394. 4 






63.46 


3.53 


59.40 


-7.59 






Mixed diet, including 
lean beef cooked in 
water 2 hours 

Total 


f 1 
2 
3 

. 4 






— 47.40 


Aib 


797.8 

846.2 

924.0 

1,607.4 


1.88 
1.93 
1.79 
1.01 


15.00 
16.33 
16.54 
16.24 


















































4,175.4 






64.11 


4.79 


63.41 


-5.49 


-34.30 




Mixed diet, including 
lean beef cooked in 
water 2 hours 

Total 

Mixed diet, including 
lean beef fried 

Total 

Mixed diet, including 
lean beef fried 

Total 


f 1 
2 
3 

4 

1 
2 
3 
4 

1 
2 
3 
4 








m 


757.4 
866.3 
93S.6 
849.9 


1.92 
1.87 
1.73 
1.83 


14.54 
16.20 
16.24 
15.55 
















-. 




























3,412.2 






62.53 


2.50 


57.07 


-7.96 


-49.80 




1 


278 


785.5 
858.5 
855.3 
825.5 


1.89 
1.75 
1..59 
1.69 


14.85 
15.02 
13.60 
13.95 


















































3,324.8 






57.42 


2.02 


53.45 


-5.99 


-37.40 




1- 


!79 


770.8 
846.8 
954.1 
862.5 

3,434.2 ■ 


1.55 
1.64 
1.45 
1.49 


11.95 
13.88 
13.84 
12.85 






















































52.52 


1.57 


52.54 


-1.55 






Mixed diet, including 
lean beef cooked in 
water 20 minutes ■ 

Total 


1 
2 

3 
4 






—9.65 


80 


661.4 

1,044.2 

997.6 

884.8 


1.S4 
1.45 
1.29 
1.60 


12.26 
15.14 
12.87 
14.16 


















































3,588.0 . 






54.43 


2.93 


53.56 


-3.80 








= 


: 


— z 


—23.80 



54 



Tablk 



24. — Quantity and nitrogen content of urine per day, total incouie and outgo of 
nitrogen, and apparent gain or losn of protein, etc.. — Continued. 



4-> 
g 

.16 


o 

a 

1 
B 

B 

C 

C 

C 

c 
c 
c 

A 
B 


Kind of food. 


I 
■"a 

(d ft 

Q 


Weight 
urine. 


Quantity of 
nitrogen in 
daily urine. 


Total quantity of .^PP^^/^i^* ^f °. 
nitrogen in- ^ + Nobody 


ft 


Urine. 


Feces. 


Food. 


Nitro- 
gen. 

Grama. 


Pro- 
tein. 


281 


Mixed diet, including 
lean beef cooked in 
water 20 minutes 

Total 


it 


Grams. 
779.5 
908.5 

1,0.52.8 
796.9 


Pr.ct. 
1.55 
1.62 
1.41 
1.71 


. 

Grams. 
12.08 
14.72 
14.84 
13.63 


Grams. 


Grams. 


Grams. 


Grains. 






































3,537.7 


\ 


55.27 


1.76 57.12 


4- nt) [ 4- 5fi 




Mixed diet, including 
lean beef cooked l)y 
broiling 20 minutes.. . 

Total 


1 

2 
\ 3 
I 4 






282 


792.4 

1,054.3 

901.0 

792.9 


1.37 
1.28 
1.37 
1.51 


10.86 
13.50 
12.34 
11.9? 






1 






















' 














3, .540. 6 


1 


48.67 


3.3i 


49.43 


—2 55 i5 94 




Mixed diet, including 
lean Ijeef cooked in 
water 2 hours 

Total 


1 
2 

1 3 
I 4 






284 


784.5 
1,380.3 
1,174.2 
1,296.2 




13. 59 










1/.91 
16.82 
16.77 


! 
































4,635.2 






65.09 


7.48 


74.86 


+2.29 +14 32 




Mixed diet, including 
lean lieef cooked in 
water 2 hours 

Total 


f 1 
4 








285 


• 789.7 
782.0 
903.6 
837.3 




16.07 
17.69 
19.93 
18.09 
















1 


































3,312.6 






71.78 


4.80 


74.19 


-2.39 1 -14.94 




Mixed diet, including 
lean beef cooked in 
water 2 hours 

Total 


f 1 

2 

3 
4 
5 






?Sfi 


1,515.1 
1,047.9 

972.8 
1,051.7 

393.8 


i.'is' 


13.44 
15.55 
16.21 
17.09 
4.45 




































































4,981.3 






66.74 


6.82 


82.. 53 


+ 8.97 1 +56.05 




Mixed diet, including 
lean beef cooked in 
water 2 hours 

Total 


1 
2 
3 
4 










287 


1,228.5 
1,310.0 
1,250.5 
1,060.5 





16.65 
16.58 
16.69 
16.06 
































1 










1 _ 
















4,851.5 






65.98 


7.84 


77.17 


+ 3.35 


+20.94 




Mixed diet, including 
lean beef coolced in 
water 2 hours 

Total 


f 1 
2 

3 

. 4 








288 


912.7 
839.3 
756.5 
854.3 


'.".". 


14.26 
15.59 
15.68 
16.46 
























































3,362.8 






61.99 


5.88 


67.68 


-.19 


— 1.19 




Mixed diet, including 
lean beef cooked in 
water 2 hours 

Total 


f 1 
2 

3 
. 4 








289 


822.9 
848.8 
873.0 
934.2 




15.98 
16.19 
17.23 
16.15 


























































3,478.9 






65.. 55 


5.40 


68.36 


-2.59 


—16.18 




Simple diet, including 
lean beef round, 
cooked in water at 
80-85° C. for 1 hour. . . 

Total 


[l 








293 


884.6 
922.7 


1.85 
2.03 


16.37 
18.73 







































1,807.3 






35.60 


3.03 


34 51 


-3.62 


-11.38 




Simple diet, including 
lean iieef round, 
cooked in water at 
80-85° C. fori hour... 

Total 


1 1 
\2 








294 


994 2 

995 3 


1.61 
1.96 


16,01 
19.51 






































1,989.5 






35.52 


1.13 


38.55 


+ 1.90 


+ 5.94 















55 

T\iii,io ■lA.—QuaiUUy and nitrogen conlenL of urine per day, total income and outgo (/ 
nitrogen, and apparent gain or loss of protein, etc. — Continued. 



4-3 

a 

a) 
1° 


1 

D 

E 

B 

A 
B 
B 
E 

B 

A 
B 


Kind of food. 




Weight 


Quai 
nitre 


itity of 
)gen in 
■ urine. 


Total quantity of 
nitrogen in— 


Apparent gain 

(+ ) or loss (-) 

to body. 


a, 


urine. ' daih 


Urine. 


Feces. Food. 

1 


Nitro- 
gen. 


Pro- 
tein. 


297 


Simple diet, including 
lean beef round, 
cooked in water at 
80-85° C. fori hour... 

Total 


{l 


Grams. Pr.ct. 
959.2 i 1.29 
1,083 I 1,98 
1,183.0 , 2.23 


Grams. 
12 37 
21.46 
26.38 


Grams. 


Grams. Grams. 


Grams. 


Grams. 


































3,225 8 






60 21 


94 60 57 


-0.58 


- 1.19 




Simple diet, including 
lean beef r o u n d, 
coolced in water at 
80-85° C. fori hour... 

Total 


[l 






300 


1,173.0 
1,361.1 
1,260.1 


1.53 
1.81 
2.04 


17.95 
24,64 
25.71 














1 




























3, 794. 2 






68 30 


2.51 76.54 


+1.91 


+ 11.94 




Simple diet, including 
lean beef round, 
cooked in water at 
80-85° C. fori hour... 

Total 


il 






301 


1,094 4 
1,112 9 
1,009.1 

3,276 4 


1 

1.51 

1.96 
2 05 


16 53 
21.81 
21 92 














































60 26 


1 79 1 Rd 09 


+ .96 


+ 6 00 




Simple diet, including 
lean beef round, 
cooked in water at 
80-85° C. for 2 hours.. 

Total 


i 1 

12 










290 


823,6 
1,134 2 


2 04 
1.06 


16 80 
18.83 






































1,957.8 




35 63 


3 06 


36 08 


-1.31 


- 8 19 




Simple diet, including 
lean beef round, 
cooked in water at 
80-85° C. for 2 hours.. 

Total 


[1 




291 


1,083 3 
1, 166 3 


1.60 
2 05 


17 33 
23 91 


























' 








2, 249 6 






41.24 


1. 68 1 48 44 


+ 2 76 


+ 17.25 




Simple diet, including 
lean lieef r o u n (1 , 
cooked in water at 
80-85° C. for 2 hours. . 

Total 


a 






292 


1,165 5 
1,078 6 


1.76 
2 04 


20 48 
21.94 


' 




































2,244 1 






42.42 


1.30 


46 75 


+ 1.51 


+ 9.43 




Simple diet, including 
lean beef round, 
cooked in water at 
80-85° C. for 2 hours. . 

Total 


If 






298 


1,259 4 
1,314 4 
1,350 2 


1 79 

1 99 

2 01 


22 54 
26 16 
27.14 


















































3, 294 






75 84 


2 90 


85 68 


+2.31 


+ 14 44 




Simple diet, including 
lean beef round, 
cooked in water at 
80-85° C. for 2 hours.. 

Total 


li 






299 


884 9 
927 3 
980 1 


1.78 
2 10 
2 15 


15 75 
19 47 
21.07 


























r 























2, 792 3 






56 29 


1.87 


61.88 


+ 1.23 


+ 7.69 




Simple diet, including 
lean beef round, 
cooked in water at 
80-85° C. for 3 hours.. 

Total 


{I 






295 


Lost. 
936 8 


















1.75 


16 39 


































.82 


25 83 


-3 89 


94 31 




Simple diet, including 
lean beef round, 
cooked in water at 
80-85° C. for 3 hours.. 

Total 


[1 












296 


774.0 
810 8 


2 03 
2 24 


15 71 
18 16 






































1,584 8 






33.87 


.83 j 


33. 24 


- .74 


4 63 
















ou 



Table 24. — Quantily and nitrogen content of umie per day. total income and outgo of 
nitrogen, ai\d apparent gain or loss of protein, etc. — Continued. 



t;,° " 



3n 



Kind of food. 



g^ I Total quantitv of M^^'l^^^.ti'? 
-i Weight Quantity of; nitrogen in— to bod v 

E of nitrogen in ' 



cc 



Urine. Feces. Food. 



Nitro- I Pro- 



gen. 



tein. 



Simple diet, including Grams. Pr.it. Grams. Grams. Grams. Grams. Grams. Grams 
lean beef round, fl; 8S0 9 100 14 19: ' 



372 E 



pan broiled {2 l,o40 2 1. 9a 25 98 

t9 



[ 3 l,li;.S 1 2C3 22. 



Total 3.350.9 



62 SO 



73 91 



73 



-17.00 



Simple diet, including 
lean beef round, f 1 ] 1,410.7 1.80 1 25 39 
pan broiled n' 2 1.005 2 04 1 20 50 



1 



3 l,2iS 3 2.20 I 26 80 



Total 3,634.0' - 72 69 2 27 



82.11 +2.SS 



-14.87 



373 



574 : F 



Simple diet, including ' P 
lean beef round, f 1 ' 1.179.1 

panbroiied \2 1,1562 

I 3 , 1,0,>2 7 



1.87 1 22 05 
2 17 25 09 
2 17 ' 22 41 



Total 1 I S,36S 



. 69 55 



1.85 



70. 56 - . 28 - 1. 75 



Simple diet, including 

lean beef round, 11 1.267.7 i 1.45 18 38 

fried in hot lard {2 1.100.6.1.8^1 2124 

I 3 , 1,000 5 2 0.- 20 71 



Total ' 3.42S S 



»00 



2 47 ; C9.27 -i-2 10 -M3.50 



375 ' E ' Simple diet, including 

lean beef round, I 1 1 1,339.8 1 67 22 S8 

fried in hot lard \ 2 1,200 8 I 1.93 l 24 io 

[ 3 95..S ' 2 11 I 20 21 



Total i 3,564.4 



67.04 



376 B 



Simple diet, including I | 

lean beef round. [1 1.0S3-2 I 1.66 ■ 17 98 

fried in hot lard \ 2 1,103.4 , 2 OD 1 22 0/ 

I 3 I 1.134.1 2 CO 23 36 



Total I 3,320 



63 41 



377 F 



Simple diet, including 
lean beef round, f 1 

roasted ■! 2 

3 



1,297.8 I 1 68 21 79 

1.325.5 ' 1 9jJ 25 58 

1.321.6 2 03 I 26 43 



3.19 



71. 60 I -1- . <6 -4- 2 88 



1.42 ; 61.93 I -}- .97 - 6 06 



Tot.al. 



37S E Simple diet, including j 

le.in beef round. (1 

roasted <l 2 

;l 3 



3,944 9 



73. SO 



1 59 SI. 47 ; 4-2 03" +12.69 



1, 161. 1 1 77 20 55 

985 7 2 07 ; 20 -^O 

1,035 2 2 21 ! 2J &S 



J. 



Total. 



S, 1S2 63 S3 



1 7i 



70 20 ' +1.54 -5-9.63 



379 B 



308 F 



Simple diet, including 
le-:n I'cef round. 

revested i 2 

3 



ii 



1,112.4 


1 95 

2 16 
2 18 


21.69 . 


11305 9 
1,280 9 


26 04 i. 
27.92 



I 



Total... 



..-.3.599 2 - 75 65 101' 77.42 



.25 -4-1.56 



Simple d;et. 
fat beef - 

cooted in -r:;--^? ;.; i i 

S>-S5' C. for 2 hours-. \ 2 

[3 



920 9 2 r^ 
97S0 2 : 
9C9 4 2 1. 



Total .---! 2. 



3l- 



60 34 2 9S 



369 I E 

I 



Simple diet, including 

fat beef shoulder, 

cooVed in water £t 

aK«s5 



I in water £t f 1 ' 918 9 i 2 IS 20 03 

C. for 2 hours.. \ 2 ; 1,099 5 ' 2 16 23 75 

; I 3 I SSS 6 2 2S 20 26 



70 47 +2 C9 4-14 94 



Total '--..| 2,907.0 



64.04 



2^ 72. So -^1.94 +12.13 



57 



Table 24. —-Quantihj and nitrogen content of urine per day, total income and outgo of 
nitrogen, and apparent gain or loss of protein, etc. — Continued. 



a 

a7 


-4^ 

2 

3 
«2 

B 

1 
1 
1 
i 

I 
B 
B 

J 


Kind of food. 




Weight 
of 


Quantity of 
nitrogen in 


Total quantity of ' APfo^'loss?'"^ 
mtrogenin- ; (+>t^Vo|y.^~^ 




>>fe urine. 

OS a 


daily unne. 


Urine. 
. Grams 


' Feces. 


Food, j Nit-- 


Pro- 
tein. 


370 


Simple diet, including 
fat beef shoulder, 
cooked in water at 
80-85° C. for 2 hours. 

Total 


; Gravis. 
f 1 1,102.9 


Pr.ct: Grams 

1. 85 ; 20. 40 

2, 26 i 22. 49 
2, 36 20. 48 


. Grams 


1 1 

[ ! 

Grams., Grams. Grams. 




u 


995 1 

867.7 




. ..:::;;:i::::::: :: """1 








1 j 








.... 




2,965 7 


! 


63 37 


1 aa 


64.31 -0 34 -5.13 




Simple diet, including 
beef ribs, roasted. . . 

Total 


1 






422 


1,176 9 

1,046 3 

918 9 


1. 87 I 22 01 
1. 84 i 19 25 
1.94 17.83 


1 


1 




1 


1 




f 


, 1 












3,142.1 




59 09 2. 02 


67.47 


+ 2.12 


+13.25 




Simple diet, including 
beef ribs, roasted 

Total 


\l 




423 


996 3 
1,029 5 
1,099 5 


1.88 
2 12 
1.81 


18 73 
21 83 

19 90 




1 


1... i 


















i 
















3, 125 3 






60.46 


1.77 


65.45 +1.07 


+ 6.69 




Simple diet, including 
beef riVis, roasted .... 

Total 










426 


1; 


!,!94.0 1 1 76 
1,164 5 1 88 


21 02 
21.89 






1 
















j 1,115 1 2.03 j 22 63 












1 








3, 473. 5 






65 54 1. 46 


72 36 i +1.79 


+ 11.19 




Simple diet, including 
beef ribs, roasted 

Total 










427 


(l.-i 1,524 4 


1.53 i 23.32 


■ 1 . 






{t 


1,536 3 
1,592 7 


1.65 
1.73 


25 35 
27.55 


; 1 ■ ■ 






! """! 












I 
B 
J 
H 

I 
B 

n 

1 


4,653 4 






76.22 


1.02 


84,85 ; +2.54 


+ 15.88 




Simple diet, including 
beef ribs, roasted 

Total 










428 


13-- 


843 
897 5 
940 4 


1.96 
2.01 
2.08 


16 52 

18 58 

19 57 






































2,680 9 






54 67 


1.61 


54 73 - . 52 


- 3.25 




Simple diet, including 
beef ribs, roasted 

Total 










429 


1; 


1,118 6 

1,053 

988 


1 78 

2 02 
2 14 


19 13 
21 27 
21.14 


1. 








1 


• 






i 


















3,159 6 






61 54 1 1 11 








Simple diet, including 









430 


(1-- 


1,226 7 
1,305 6 
1.715.9 


1 88 
1.95 
1.54 


23 06 

25 50 

26 43 


: !.... 1 




beef ribs, roasted '{2.. 


' 1 




Total 


13.. 


1 i 










4,248 2 






74 99 3.17 85 16 +2.33 


+ 14.56 




Simple diet, including 
veal leg, roasied 

Total 1 

Simple diet, including 
veal leg, roasted 

Total 








380 


1; 


978 5 
1,361.1 
1,240 6 


2 22 
2 18 
2 31 


21 72 
29 67 
28.66 


1 i . ' 




i - : , 






I ' 1 ■ 








! 






2, 580 2 




80 05 j 2 95 79.52 -1.16 


- 7.25 










382 


1; 


1,315 1 2 06 
1,288 2 09 
1, 480 2 2. 27 


27 09 
26 92 
33.60 


1 ; 






1 






r _ ^ .... 


1 








4,083 3 






87.61 


3.42 


101.18 1 +3. £8 


+21. 13 




Simple diet, including 
veal leg, roasted 

1 

Total 










383 


1; 


1,090 3 
1,180 2 


1.81 
2 00 


19 73 
23.61 
24 38 




1 


















1, 177. 9 2 07 












3, 448 4 1 






67.72 


1.59 


69 S9 


+ .03 


+ .19 




Simple diet, including 
veal leg, roasted L 

Total 








419 


It. 

3.. 


972 

995.7 

1, 152. 5 


2 19 
2 23 
2.35 


21 29 

22 20 
27 C9 




1 




















.......1 








3, 120 2 






70. f 8 


2 13 1 72 17 


- .18 


- 1.13 




Simple diet, including 
veal leg, roasted < 

Total 










420 


Il- 
ls:: 


1,246.4 
1,040.9 
1,115.0 


2.04 
2.20 
2.17 


25 43 
22 90 
24 20 






































3, 402. 3 






72.53 


1.03 


79.05 




1 


: 















58 



Tarlk 24.--Quant/ity and nitrogen content of urine per day, total income and outgo oj 
nitrogen, and apparent gain or loss of protein, etc.— Contimiod. 



§ 

$6 
3Z 


! 


Iviiui of food. 

Simple diet, including 
veal leg, roasted 

Total 


•^ " \\'cight 
>.^ urine. 


Quantity of 
nitrogen in 
daily urine. 


Tot; 


1 quantity cf ! Apparent gain 
irclgeninl ;(+) ^bo^d^.^-^ 


=■1 S 


Urine. 
Grams. 


Feces. Food. 


Nitro- 
gen. 


Pro- 
tein. 


421 


B 

H 
I 
B 

I 

B 

I 
J 


Grams. 
|1.- 1,004.8 


Pr.ct. 
1.90 


Grams. 
20 23 
22 50 
24.52 


j 
Grams. Grams. \ Grams. 


Grams. 




^2.. 1,13C.4 
l3.. 1,184.4 


1.98 
2.07 





































3,385 6 






67. 25 


0.94 


67.36 


-0.28 


- 1.75 




Simple diet, including 
mutton leg, roasted.. 









381 


fl.. 905 8 
■^2... 1,182 5 


2 27 
2.18 
2.15 


20 56 
25 78 

24.78 
























3.. 


1,142 9 
























Tota 1 




3,231.2 






70.91 


3.78 


73.40 


- .43 


- 2.69 




Simple diet, including 
muttoii leg, roa.sted.. 

Total 


1; 






3S4 


1,236 
1,481.5 
1,329.5 


2 12 
1.98 
2 03 


26 20 
29 33 
26.99 


i 











1 






1 










t 








4,047.0 




82.52 


3.53 1 92.57 


4-2 17 


j-i-a Kft 




Simple diet, including, 
nuitton leg, roasted. . 

Total 








385 


1; 


1,110 1 

1,266 5 

880.7 


1 64 
1.88 
1.95 


18.21 
23.81 
17.17 












































3,257.3 






59.19 


1.82 


80.20 


-Lft 40 i -1-40 00 




Simple diet, including 
pork (fresh ham), 
roasted 










386 


i;; 


1,121.3 
1,258 2 
1, 132. 2 


2.18 
2 23 
2.25 


24,45 
28 06 
25. 45 


», 




















Total 












1 










3,510.7 






77.96 


2.05 


90.43 


+3.47 +21.69 




Simple diet, including 
pork (fresh ham), 
roasted 

Total 










387 


1; 


1,196 7 
1,248 7 
1,083.1 


1.91 
2 06 
2.11 


22.86 
25 72 
22.85 




























1 










1 






3,528.5 






71.43 


1.70. 


79.05 


+ 1.97 j +12.31 




Simple diet, including 
pork (fresh ham), 
roasted 










424 


1; 


1,253.4 

1,030 3 

932.2 


1.63 
2 22 
2 37 


20.43 
22 87 
22.09 




- 




! . 










1 




Total 








1 














r.'^Miu 






65.39 


1.38 


62.62 


- .47 


- 2.94 




Simple diet, including 
pork (fresh ham), 
roasted 

Total 










425 


i;; 


1,332 6 
1,542.3 
1,511.1 


1.41 
1 31 
1.42 


18.79 
20.21 
21.46 


















































4,386.0 






60.46 


2.14 


69.10 


+2.17 


4 13. 56 














No definite conclusion regarding gain or loss of protein can be 
drawn from the above data, because nothing was known concerning 
the diets and the income and outgo of nitrogen of the subjects previous 
to the beginning of the experiment; hence it is impossible to tell to 
what extent the nitrogen of the urine collected pertains to the food of 
the experimental period and how much should be ascribed to food 
eaten previous to the experiment. Furthermore, the lag in the excre- 
tion of nitrogen from the experimental diet might extend beyond the 
time of ending the last urine period. For these reasons the difference 
between income and outgo of nitrogen has been designated "apparent" 
gain or loss in the above table. It is believed, however, in the light of 
present available knowledge concerning the lag in nitrogen excretion, 



59 

that the data for the second and third days of the experimental periods' 
show with some approximation to accuracy the actual balance between 
income and outgo of nitrogen under the conditions of the experiments, 
and from these some estimate can be formed regarding the balance for 
the whole period. 

The gains and losses were very fluctuating, and there were some 
noticeable losses and some decidedly large gains of nitrogen. On the 
whole, the gains were much more numerous than the losses, and the 
average amount gained was so much greater than that lost that it 
seems fair to assume that the diets used in the experiments were at 
least sufficient to supply the needs of the subjects for nitrogen. 

INVESTIGATIONS ON THE EASE OR RAPIDITY OF DIGESTION OF 

MEAT. 

The ease or rapidity with wliich different foods may be digested is 
of some significance. For instance, two kinds of food may be equal 
to each other in respect to the quantities of the different nutrients 
which they contain and the thoroughness with which they may be 
digested, but one may be more easily digested than the other and con- 
sequently in certain circumstances somewhat the more advantageous. 
Different meats, therefore, or similar kinds of meats cooked in diif erent 
ways, though in other respects apparently of equal nutritive value, 
ma}^ differ in actual value because of variation in the ease of digestion. 

Several investigators have attempted to study the ease or rapidity 
with which different foods maybe digested, and among the investiga- 
tions are some with meats cooked in various ways. Two methods 
have been followed in these investigations, one consisting of direct 
examination of the stomach contents at different periods after eating 
and the other comprising experiments with artificial digestive solu- 
tions. Reference is here made to some of these investigations, but the 
purpose is to give an idea of the nature of the work that has been 
undertaken and of the results obtained rather than to include a com- 
plete summary of what has been accomplished. 

EXAMINATION OF STOMACH CONTENTS. 

Among the most famous of such experiments, in which the time of 
digestion in the stomach of meats prepared in dift'erent ways was 
studied, are those made by Beaumont ° many years ago. His subject 
was an otherwise normal man who had been shot throuo;h the stomach 
and whose wound had so healed as to leave a valvular opening into the 
stomach through which its contents could be observed and removed. 
Beaumont reports that meats remained in the stomach for the periods 
given in Table 25. 

a The Physiology of Digestion, 2. ed. Burlington, Vt., 1847. 



60 



Table 25. — Results of observations on gastric digestion. 



Kind of meat. 



Turkey ,domestic 

Do 

Beef, fresh, lean, rare 

Beef, fresh, lean, dry 

Beefsteak 

Beef with salt only 

Beef with mustard, etc . . . . 

Beef 

Beef, old hard, salted 

Fork , stea k 

Pork, fat and lean 

Pork, recently salted 





Mean 


Method of 


time of 


cooking. 


Ch^TTlifi- 




cation. 




H. m. 


Roasted .. 


2 30 


Boiled.... 


2 25 


Roasted.. 


3 00 


do 


3 30 
3 00 


Broiled . . 


Boiled 


2 4.5 


do.... 


3 00 


Fried..... 


4 00 


Boiled 


4 15 


Broiled... 


3 15 


Roasted . . 


5 15 


Boiled 


4 30 



Kind of meat. 



Method of 
cooking. 



Fried... 
Broiled. 
Raw 



Pork, recently salted . . . 

Do 

Do 

Do I Stewed. 

Mutton, fresh Roasted . 

Do I Broiled. . 

Do BoUed... 

Veal, fresh Broiled. . 

Do Fried.-... 

Fowls, domestic ! Boiled. . , 

Do Roasted. 



Mean 
time of 
chj'mifi- 
cation. 



H. m. 
4 15 
3 15 



00 
00 



3 15 
3 00 



00 
00 
30 
00 
00 



From experiments with a boj;^ having a gastric fistula, Ufl'ehnan'* 
drew, in effect, the folhnving conchisions regarding the time of gastric 
digestion of different kinds of meats: All the observations firmly 
established the fact that the boy digested raw scraped beef more 
quickly than finely chopped ham, but not so quickly as roasted beef. 
The first was undoubtedh^ more quickly penetrated by the gastric 
juice. However, it fell apart into minute»iibers less easily, and the 
conclusion may safely be drawn that the digestion of the raw meat 
took place somewhat more slowly than that of the roasted. 

Jessen ^ studied the gastric digestion of raw and cooked beef and 
raw mutton, veal, and pork. His subject was a health}^ man, from 
whom, by means of a stomach pump, the contents of the stomach 
were removed at intervals after the food was eaten. He found that 
100 iirams of the various kinds of meat left the stomach in the time 
given below : 

Hours. 

Beef, raw, shredded 2 

Beef, boiled , rare 2h 

Beef, boiled, well done 3 

Beef, broiled , rare 3 

Beef, broiled, well done - 4 

Mutton, raw, shredded , 2 

Veal, raw, shredded 2i 

Pork, raw, shredded 3 

^lore recent experiments of similar nature, from which much of 
the current information regarding the rates of gastric digestion of 
diflerent foods has been derived, are those by Penzoldt "^ and by 
Verhaegen.'' 

It will be observed that experiments of this nature show chiefly 
the lenoth of time that foods remain in the stomach and the time 

a Deut. Arch. Klin. Med., 20 (1877), p. 535. 

i'Ztschr. Biol., 19 (1883), p. 129. 

^Deut. Arch. Klin. Med., 51 (1893), p. 535. 

d Physiologie et Pathologic de la Secretion Gastrique, Paris, 1898. 



61 

required for reduction of the food to the condition of chyme, in which ' 
condition it passes to the intestine. But digestion is by no means 
completed in the stomach. In fact the material from the stomach 
is acted upon much further by the ferments in the intestine, and 
these experiments show nothing regarding intestinal digestion. 

ARTIFICIAL DIGESTION EXPERIMENTS. 

Artificial digestion experiments — that is, those in which the action 
of the digestive juices is studied outside of the body — are open to 
much the same objection as direct observation of the gastric con- 
tents. In the first place, it is im.possible to reproduce artificially all 
the conditions of natural digestion, aside from temperature and 
strength of the digestive fluids, which aid in dissolving the food, and 
doubtless for this reason artificial digestion is always slower than 
natural. Beaumont " made such experiments in connection with his 
natural gastric experiments, and found that to produce the same 
effect on the food outside of the body as in it required rarely less 
than twice, and often three and one-half times, as long a period of 
digestion. Furthermore, artificial-digestion experiments, as most 
commonly made with pepsin, show nothing of the digestibility of 
fats, which depends largely on their saponification in the intestines, 
and, so far as the authors have learned, little work has been done 
with meats to study the effect of trypsin of the pancreatic juice in 
breaking down peptones into simpler, more absorbable bodies, so 
that even as regards the digestibility of protein the results of experi- 
ments of this nature must be regarded as incomplete. Nevertheless 
since Stutzer ^ in 1880 proposed the method of making such experi- 
ments, which, considerably revised and elaborated, is still most com- 
monly used, much valuable work of this nature has been done. Very 
little, however, refers especiall}^ to the digestibility of meat prepared 
in difi"erent ways. 

Among the earliest artificial digestion experiments with meats w^ere 
those carried on by Jessen " in connection with liis study of natural 
digestion. In these experiments 250 grams of beef from a steer about 
2 years old were freed as completely as possible from sinew, fat, 
gristle, and bone, and similar portions of it were boiled until half 
done, well boiled, roasted underdone, and well roasted. The cooked 
meats were then partially dried and samples of each, and also of the 
raw meat, weighing 25 grams were treated with 400 cubic centimeters 
of an acid pepsin solution containing in some cases 1 gram and in 
others 2 grams of pepsin per liter of either 0.1 or 0.2 per cent hydro- 
chloric acid. The digestion was continued for twenty-four hours, 
with frequent stirring, at a temperature of 37° C. The insoluble 

a Op. cit., p. 292. bjom. Landw., 28 (1880), pp. 195, 453. 

cZtschr. Biol., 19 (1883), p. 129. 



62 

residue was then removed by filtration, dried at 100-110° C. for two 
to five hours, and weiglied. In these tests the following coefficients 
of digestibility were obtained: Raw beef 77.32, boiled beef underdone 
62.02, well-boiled beef 28.20, roasted beef underdone 60.96, and well- 
roasted beef 31.72 per cent. From these results it was concluded that 
raw meat was more easily digested than cooked meat. 

Chittenden and Cummins " made a few experiments on the relative 
digestibility of raw and cooked meats in connection with artificial 
digestion experiments with fish. In each case 20 grams of meat 
either raw or cooked in a steam bath and freed as completely as pos- 
sible from sinew, fat, skin, and bone were treated in a beaker with 
200 cubic centimeters of a digestive solution containing 5 grams of 
pepsin in 1,000 cubic centimeters of pure hydrochloric acid of exactly 
0.2 per cent strength. The digestion was continued for twenty-two 
hours at a temperature of 38° to 40° C. with occasional stirring. At 
the end of this period the solution was cooled to 20° C, diluted to 
250 cubic centimeters, thoroughly mixed, and then filtered through 
a dry filter. Of the clear filtrate 50 cubic centimeters were evapo- 
rated to dryness in a weighed dish after the addition of 5 cubic centi- 
meters of a standard solution of sodium carbonate of such strength 
as to exactly neutralize the acid present. The residue was then 
dried to constant weight at 110° C. Control experiments were also 
made with the acid pepsin solution alone, and the residue obtained 
from the blank experiment was subtracted from the weight of the 
residue left by the evaporation of the 50 cubic centimeters of the 
digested mixture. The quantity thus obtained was multiplied by 5. 
which gave the amount of matter (peptones and intermediate prod- 
ucts together with some salts) dissolved from 20 grams of meat. 
From their experiments these investigators found that under the 
conditions mentioned less of the cooked meat was digested than of 
the raw meat. 

Popoff '' conducted experiments on the rapidity of digestion in 
wliich he used, among flesh foods, beef prepared in different ways. 
His digestive solution was prepared by adding 8 grams of pepsin and 
4 grams of hydrochloric acid to 1 liter of water. The quantity of this 
mixture used for each sample was diluted by an equal volume of 
water. The beef, which was comparatively lean, was scraped as free 
as possible of connective tissues and divided into portions of equal 
weight to be used for analysis and experiment. In the one series of 
experiments part of the meat had begun to decompose slightly, but 
it was nevertheless used in order to test its comparative digestibility. 
The cooking was done in a steam apparatus without the addition of 
water in the first two series and with 100 cubic centimeters of water 

rtAmer. Chem. Jour., 6 (1884-85), p. 318. 
b Ztschr. Physiol. Chem., 14 (1890), p. 524. 



63 

in the last two. The artificial digestion was conducted at a tempera- 
ture of 39° C. and continued five and one-half hours m the first and 
second series, four hours in the tliird, and three hours in the fourth. 
At the end of these periods peptonization was arrested by the addition 
of 80 milligrams of calcium carbonate. The quantity of protem m 
the undigested portion was determmed and subtracted from that 
found in a corresponding sample not digested. From his experi- 
ments Popoff concluded that beef is more readily digested in the raw 
than m cooked condition; that cooking decreases its digestibility; 
that the longer it is cooked the more difficult its digestibility becomes. 

Stutzer" also made some experiments by the method of artificial 
digestion which he devised to determine whether raw ineat is as 
rapidly digested as cooked meat. For this purpose he divided a 
large piece of good lean beef into two parts, one of which he cut into 
coarse pieces, which he dried at 40° C. and ground fine. The other 
part he cooked in an ordinary manner, and then cut it up, dried, 
and ground it in the same way that he did the uncooked part. He 
treated small portions of each in the same manner with digestive 
solutions. He used solutions of different strength, but in each case 
digestion was continued at 38° to 40° C. for thirty minutes. From a 
comparison of the proportions of the original nitrogenous material 
that were actually dissolved he drew a conclusion in harmony with 
that of Popoff's, that the digestibility of the meat was decreased by 
cooking. 

The more specific object of some of the above-mentioned investi- 
gations was to determine the total amount of nitrogenous material 
that would be digested under certain conditions. Thev do not give 
much information regarding the ease of digestion. The experiments 
made by Popoff and Stutzer, however, were made, as explained, to 
compare the relative ease of digestion of raw and cooked meat; but 
these give practically no information as to whether differences in 
methods of cooking the meat have different effects upon the ease of 
digestion. 

INVESTIGATIONS HERE REPORTED. 

Some knowledge regarding the effects of different methods of cook- 
ing upon the ease or rapidity of digestion of meat seemed especially 
desirable. The investigations undertaken by the authors regarding 
the various factors that influence the nutritive value of meat seemed 
to offer very favorable opportunity for a study of this subject. 
Accordingly, in connection wdth the experiments on the complete- 
ness of digestion reported on preceding pages of this bulletin, atten- 
tion was devoted to a study of the relative ease of digestion of different 
kinds and cuts of meat, cooked in different ways. 

"Landw. Vers. Stat., 40 (1892), p. 321. 
4663— Rule 193—07 5 



64 

It was, of course, impossible to make such study by observation 
of the natural process of digestion with the different subjects, and 
none of the data actually obtained in the natural digestion experi- 
ments throw any light upon the ease of digestion of the meats used. 
It is possible that in time our knowledge of the metabolic products 
may be such that these will afford some indication of the ease of 
digestion, but as yet it is entirely inadequate. The only method 
available, therefore, was that of artificial digestion. The limitations 
of such experiments in a study of total digestibility have already 
been pointed out. Similar criticism might also be made of the use 
of such methods for a study of ease of digestion. It seemed reason- 
able to believe, however, that the method could be so adapted as to 
give approximately correct evidence of the rapidity with which pro- 
tein may be peptonized. Incomplete as such evidence may be, it 
would seem possible to make it trustworthy so far as it applies, and 
in the present lack of more definite information it would be of great 
practical value in dietetics, especially for dyspeptic and other persons 
who must be relieved to some extent of digestive effort. 

In all, 99 artificial digestion experiments were completed as de- 
scribed in detail on the following pages. r Of these 7 were of a pre- 
liminary nature, made in connection with the study and development 
of method described below; the other 92 were conducted according 
to the method finally adopted. 

DEVELOPMENT OF METHOD. 

None of the methods followed in the earlier investigations men- 
tioned was especially adapted, m all particulars, to the purposes of the 
experiments which it was desired to undertake; nor could the present 
authors discover any investigations m which the Stutzer method 
of artificial digestion had been modified in such a way as to show 
the relative ease or rapidity of digestion of different foods. Atten- 
tion had to be devoted at first, therefore, to a development of a 
suitable method of procedure. The various factors that had to be 
taken into account in order to provide a method by which uniformity 
of results under identical conditions could be secured are here con- 
sidered in more or less detail. 

Composition of the digestit^e solution. — ^A few preliminary tests 
were made, to determine the most suitable composition of digestive 
solution. In each case 2.5 grams of pepsin were dissolved in 1 liter 
of hydrochloric acid; but three strengths of acid were used — one of 
0.2 per cent, one of 0.33 per cent, and one of 0.2 per cent at the 
beginning but with subsequent additions of 10 per cent acid until 
the strength of the acid in the solution was 0.5 per cent. The most 
uniform and satisfactory results obtained were those with a digestive 
solution made by adding 2.5 grams of pepsin to 1 liter of 0.33 per 



65 

cent hydrochloric acid, and this was adopted as a standard digestive 
solution for the preliminary investigations. Of this standard solution 
the same amount, 100 cubic centimeters, was used for each sample. 

Proportion of meat to a given amount of digestive solution. — The 
total action of the digestive solution is appreciably affected by the 
quantity of material to be dissolved. A given amount of the solu- 
tion will digest a smaller sample more thoroughly than a larger one 
when the other conditions are the same in both cases. It was not 
the purpose of these experunents to determine the maximum digesti- 
bility of meat under given conditions, but it was believed that the 
])articular ])urpose of the investigation could be more satisfactorily 
attained if the size of the sample were such that its retarding influence 
upon digestion would be minimized. From the results of study of 
this question it was concluded that from 0.8 to 1.2 grams of dry 
powdered meat was the most suitable size of sample to be used with 
100 cubic centimeters of the standard digestive solution. 

This proportion is decidedly smaller than that used by some of 
the other investigators mentioned above, notably Jessen, and 
Chittenden and Cummins. It was found, however, that the total 
digestibility obtained with the smaller sample was in the main 
larger than those obtained by other investigators, and the results 
with similar samples were much more concordant. 

Temperature of digestion. — In so many of the previous investiga- 
tions the temperature of 38° to 40° C. had been found satisfactory 
that it was adopted in the present experiments without much pre- 
liminary testinc^. 

Filtering the digested product. — The effect of the digestive solution 
upon the meat was determined by comparing the quantity of nitrogen 
in the material before digestion with that remaining in the undigested 
residue. Because of the slowness with which the solution filtered, 
an attempt was made at first to determine the nitrogen in aliquot 
parts of the filtrate, as w^as done by Chittenden and Cummins and 
by Stutzer. The unavoidable evaporation of the solution, the use 
of large factors to fiiid the total amount digested, and the necessary 
corrections for nitrogen of pepsin, afforded so much opportunity for 
error that this method was soon discarded. Efforts were then made 
to provide some method for more rapid filtration. Qualitative filter 
paper was tried, but though the solution passed through it rapidly 
the undigested residue was not all retained. The suction pump 
with hardened filter paper was inconvenient, as it required too much 
attention and was about as slow as without the use of the pump. 
The method that proved most satisfactory, and which was finally 
adopted, is as follows: Hardened quantitative filter paper, 9 centi- 
meters in diameter, containing 0.1 milligram of nitrogen per paper, 
was folded in 32 sectors so as to present a corrugated surface and 



66 

expose practicably all of it to the filtering solution. Such folded 
filter papers were placed in two funnels, held one above the other, 
and the flask containing the solution inverted in the top fuiuiel so 
that the solution would run into the filter automatically. Such an 
arrangement required very little watching. When the solution had 
all passed through both papers the residue was washed free from 
pe])t()nes, and both filt(>r paj:)ers, with their residues, were put into 
the Kjeldahl flasks for the nitrogen determination. The tops of the 
filter papers were cut oft", when necessary and practicable. 

Duration of the digestive period. — Several preliminary experiments 
were made to determine what length of time the digestion should be 
continued. Chittenden and Cummins digested their samples for 
twenty-two hours; but their object was to ascertain total or maximum 
digestibility. Stutzer, on the other hand, in studying the relative 
ease of digestion of raw and cooked meat, digested his samples only 
thirty minutes. 

The results obtained in the first of the preliminary tests in the 
present investigation are reported in Table 26. All the samples used 
in the tests included in the upper portion of Table 26 were from the 
same cut of beef round from an animal about 5 j^ears old. Portions 
of this cut were cooked as follows: In water at 80° to 85° C. for two 
hours and for five hours; pan ])roiled, i. e., fried without added fat; 
and fried in hot lard. Several samples of the meat cooked by each 
method, and also of the uncooked meat, were digested in the fresh 
state (i. e., not dried and ground). In each case the sample was 
treated with 100 cubic centimeters of digestive solution containing 
2.5 grams of pepsin solution in 1 liter of 0.33 per cent hydrochloric 
acid, and the digestion was continued at 38° to 40° C. for twenty-four 
hours. 

In the tests included in the lower part of Table 26 the digestion 
was conducted in exactly the same way, but the samples, which were 
all lean beef round, were from different animals. Nos. 1107 and 
1108 were parts of the same cut from an animal 6 years old, the former 
uncooked and the latter cooked in water at 80° to 85° C. tor two 
hours. No. 1116 was from an animal about 5 years old, and was 
cooked in water for two hours. Nos. 1119 and 1120 were portions of 
the same cut from an animal 6 years old, the former uncooked and 
the latter cooked in water two hours. Nos. 1130 and 1131 were por- 
tions of the same cut from an animal 4 years old, the former uncooked 
and the latter cooked in water one hour. No. 1148 was from an 
animal 2 3'ears old and was cooked in water three hours. In each 
case the meat was dried and ground fine, and the samples for diges- 
tion were weighed from the finely ground substance. 



67 

Table 26. — Tests of effect of acid- pepsin solution upon fresh aiul air-dried samples of 

raw and cooked beef digested for 24 hours. 





Description of samples. 


Nitrogen in- 


- 


Propor- 
tion of 

total 
nitrogen 

indi- 
gested 
material. 


Lab- 
ora- 
tory 
No. 


Meat. 


Undi- 
gested 
portion. 


Digested 
portion. 


119.T 


Tests with fresh samples. 
Beef round, raw . . ; 


Gram. 
0. 1067 
.0949 

. .1114 
.1310 
.1232 
.1239 


Gram. 

0.0026 
. f)02S 
.0032 
.0036 
.0031 
.0032 


Gram. 
0. 1041 
.0921 
. 1082 
.1274 
.1201 
.1207 


Per cent. 
97.56 


1195 


.do . 


97.07 


1195 


do 


97.13 


1195 


.do 


97.25 


1195 


do 


97.48 


1195 


do 


97.42 




Average ofStests 






.1152 


.0031 


.1121 


97.31 




Round, cooked 2 hours in water at 80° to 85° C 

do 

. . . ..do 




1199 
1199 
li99 


.0888 
.0852 
.1000 
.0835 
.0909 


.0023 
.0020 
.0026 
.0021 
.0025 


.0865 
.0832 
.0974 
.0814 
.0884 


97.41 
97.65 
97. 40 


1199 


.do 


97.49 


1199 


....do 


97.25 










.0897 


.0023 


.0874 


97.44 




Round, cooked 5 hours in water at 80° to 85° C 

.do 




1200 
1200 


.0953 
.0843 
.0887 
.0908 
.0981 
.0735 


.0028 
.0028 
.0026 
.0027 
.0030 
.0022 


.0925 
.0815 
.0861 
.0881 
.0951 
.0713 


97.06 
96.68 


1200 


...do 


97.07 


1200 


.do 


97.03 


1200 


do 


96.94 


1200 


do 


97.01 




Average of 6 tests 






.0885 


.0027 


.0858 


96.95 




Round, broiled or "dry fried " 




1197 


.0688 
.0867 
.0780 
.0790 
.0728 


.0025 
.0030 
.0029 
.0026 
.0027 


.0663 
.0837 
.0751 
.0764 
.0701 


96.37 


1197 


do 


96.54 


1197 


do 


96.28 


1197 


...do 


96.71 


1197 


do 


96.29 




Average of 5 tests 






.0770 


.0027 


.0743 


96.49 




Round, fried in hot lard 




1198 


.0765 
.0631 
.0672 
.0803 
.0783 
.0724 


.00.37 
.00.32 
.0033 
.0040 
.0035 
.0036 


.0728 
.0.599 
.0639 
.0763 
.0748 
.0688 


95.29 


1198 


. .do 


94.93 


1198 


do 


95.09 


1198 


.do 


95.02 


1198 


do 


95.53 


1198 


do 


95.03 




Average of 6 tests 






.0730 


.0036 


.0694 


95.07 




Tests with air-dried samples. 




1107 


.1450 
.1237 
.1325 


.0031 
.0024 
.0025 


.1419 
.1213 
.1300 


97.86 


1107 


Round, raw, 2d test 


98.06 


1107 


Round, raw, 3d test . . 


98.11 










.1337 


.0027 


. 1310 


97.98 




Round, boiled 2 liours, 1st test 




1108 


.1264 
.1199 


.0025 
.0030 


. 1239 
.1169 


98.02 


1108 


Round, boiled 2 hours, 2d test 


97.50 




Average of 2 tests 






.123; 


.0027 


.1204 


97.87 




Round, boiled 2 hours, 1st test .. .. 




1116 


.1203 
.1254 
.1432 


.0029 
.0029 
.0035 


.1174 
.1225 
.1397 


97.59 


1116 


Round, boiled 2 hours, 2d test 


97.68 


1116 


Round, boiled 2 hours, 3d test 


97.56 




Average of 3 tests 






.1296 


.0031 


.1265 


97.61 




Round, raw, 1st test 




1119 


.1223 

.1294 
. 1386 


.00.30 
.0030 
.00.32 


.1193 
.1264 
.1354 


97.55 


1119 


Round, raw, 2d test . . . 


97.68 


1119 


Round, raw, 3d test 


97.69 




Average of 3 tests 






.1301 


.0031 


.1270 


97.62 




Round, boiled 9. hours, 1st, test 




1120 


.1275 
.1193 
.1350 


.0030 
.0028 
.0031 


. 1245 
.1165 
.1319 


97.65 


1120 


Round, Ijoiled 2 hours, 2d test 


97.65 


1120 


Round, boiled 2 hours, 3d test '. 


97.70 




Average of 3 tests 






.1273 


.0030 


.1243 


97.64 









68 



Table 26. — Ttsts of effect of acid-pepsin solution upon fresh and air-dried samples of 
raw and cooked beef digested for 2Jt hours — rontiniied. 



Lab- 
ora- 
tory 
No. 



1130 
1130 



1131 
1131 
1131 



1148 
1148 
1148 



Descript ion of samples. 



Trstx with air-drird .tamptr.s — Continued. 

Round, raw, 1st test 

Round, raw, 2d test 

Average of 2 tests 

Round, boiled 2 hours, 1st test 

Round, l)oiled 2 liours, 2(1 test 

Round, boiled 2 hours, 3d test 

Average of 3 tests 

Round, boiled 2 hours, 1st test 

Round, boiled 2 hours, 2d test 

Round, boiled 2 hours, 3d test 

Average of 3 tests 

Average of 8 series of tests 



Nitrogen in- 



Meat. 



Oram. 

0.1517 

.2063 



.1790 



.1796 
. 1258 
.1178 



Undi- 
gested 
portion. 



Gram. 
0.0044 
.0046 



.0045 



.0043 
.0024 
.0022 



.1411 



.0030 



.1211 
.1456 

.1287 



.0033 
.0047 
.0037 



Digested 
portion. 



Gram. 

0. 1473 

.2017 



.1745 



.1753 
.1234 
.1156 



Propor- 
tion of 
total 
nitrogen 
in di- 
gested 
material. 



Per cent. 
97.10 
97.77 



97.49 



97.61 
98.09 
98.13 



.1381 



.1178 
.1409 
.12;"iO 



.1318 



.1370 



.0039 



.1279 



.0032 



.1337 



97.87 



97.28 
96.77 
97. 13 



97.04 



97.59 



From the results of these tests it seemed quite evident that the 
nitrogenous material of the meat was rather completely dissolved 
when the digestion was continued for twenty-four hours. Further- 
more, it also appeared that there was no material difference in the 
thorougliness of digestion whether the meat was uncooked or cooked 
in water for two or for five hours. This was about equally true 
whether the fresh or air-dried samples were considered. In the case 
of the fresh pan broiled and fried meats the digestion was a little less 
thorough, but the differences were not very large. It seemed appar- 
ent from these tests that j^ractically notliing could be learned regard- 
ing ease of digestion if the action of the pepsin solution used were 
allowed to continue twenty-four hours. It would be impossible to 
make sufficient (Hfl'erentiations when the differences were small. 

ChecJdng the action of the digestive solution. — Attention was next 
devoted to a consideration of the question whether diflerences in the 
ease of digestion, if there were anv, could be determined bv continu- 
ing the digestion for shorter periods. In order to accomplish this, 
some means of checking the action of the digestive solution had to be 
found, because the filtering process is at best slow, requiring twenty- 
four to twenty-five liours, and would afford opportunity for consid- 
erable differences in results if the action of the pepsin were allowed to 
continue unchecked . 

The effect of lowering the temperature of the solution was first 
tested. Chittenden ° suggests that a lowering of the temperature 
below 38° C. causes an immediate effect upon proteolysis. He states 



o Digestive Proteolysis, p. 18. 



69 



that '^ exposure to a low temperature retards proteolytic action doubt- 
less in the same manner that cold checks or retards other chemical 
changes." In accordance with tliis idea, experiments were made to 
determine the action of the pepsin solution at room temi:>erature 
(22° to 26° C.) and at the temperature of the refrigerator (4° to 5° C.) 
to learn whether in that way the action of the pepsin could be stopped. 
The results of these experiments are given in Table 27. The samples 
used were the same as in the tests given in Table 26, and the other 
conditions aside from temperature were identical with those of the 
experiments there reported. The tests were made in duplicate or 
triplicate in each case. 



Table 27. — Tests of effects of low temperature upon the action of the acid-pepsin solution. 




Description of sample. 


Digested at 22° to 26° C. 


Digested at 4° to 5° C. 




Nitrogen in- 


Pro- 
por- 
tion of 
total 
nitro- 
gen in 
digest- 
ed ma- 
terial. 


Nitrogen in- 


Pro- 


Sample 

No. 


Total 
sam- 
ple. 


Undi- 
gested 
por- 
tion. 


Digest- 
ed por- 
tion. 


Total 
sam- 
ple. 


Undi- 
gested 
por- 
tion. 


Digest- 
ed por- 
tion. 


tion of 
total 
nitro- 
gen in 
digest- 
ed ma- 
terial. 


1107a 
1107b 
1107c 


Lean beef round, raw 

do 

do. . 


Gram. 

0. 1219 
. 120o 
.1203 


Oram. 

0. 0054 
. 005.3 
.0047 


Gram. 

0. 1165 
.1153 
.1156 


Per ct. 
95.57 
95.61 
96.09 


Gram. 
0. 1155 

.1244 
.1162 


Gram. 

0.0108 
.0101 
.0114 


Gram. 

0. 1047 
.1133 
.1048 


Per ct. 
90.65 
91.08 




Average 


... _ 




.1209 


.0051 


.1158 


95.76 


.1187 


. 0108 1 . 1076 


90.64 




Lean beef round, cooked 
in water 2 hours... 




1116a 


.1247 
. 1282 


.0037 
.0046 


.1210 
.1236 


97.03 
96.41 


.1290 
.1379 


.0098 
.0126 


.1192 
.1253 


92.40 


1116b 


do 


90.86 




Average. 






. 1264 


.0041 


.1223 


96.72 


.1335 


.0112 


.1223 


91.63 




Lean beef round, raw 

do 

.do... . ... 




1119a 
1119b 
1119c 


.1182 
.1196 
.1281 


.0055 
.0057 
. 004.1 


.1127 
.1139 
.1236 


95.35 
95. 23 
96.49 


.1292 
.1244 


.0092 
.0085 


.1200 
. 11.59 


92.88 
93.17 




Average. 














,1220 


.0052 


.1167 


95.69 


.1268 


.0089 


.1179 


93.02 









On comparing these results with the ones given in Table 26, it was 
plain that with the standard digestive solution acting for twenty-four 
hours the digestion was nearly as thorough when the temperature was 
22° to 26° C. as when it was kept at 38° to 40° C, and even at the 
temperature of 4° to 5° C. it was only a little less complete. It was 
evident, therefore, that lowering the temperature of the solution 
would not stop the action of the pepsin sufficiently for the purpose 
of these experiments. 

Attention was then turned to the effect of different substances upon 
enzyms. Kuhne "■ has pointed out that pepsin is destroyed by 
digestion with alkaline solutions. Bertels ^ and Dubbs " found that 
large amounts of chloroform decrease the digestive power of pepsin. 

oVerhandl. Naturhist. Med. Ver. Heidelberg, Feb., 1876. 
fcArcli. Path. Anat. u. Physiol. [VirchowJ, 130 (1892), p. 497. 
clbid., 134 (1893), p. 519. 



70 



Other investigators have found various other substances to have simi- 
lar effects. In connection with the present investigation, chloroform, 
mercuric chlorid, and formalin were tested. Chloroform slightly 
precipitated the peptones or the intermediate products of the action 
of pepsin upon proteids. Mercuric chlorid also tended to form a 
slight precipitate. For this reason the use of these two substances 
was abandoned. 

Formalin produced no precipitate, but apparently it did not com- 
pletely check the action of the pepsin. A series of experiments were 
made, however, to determine whether it could not be satisfactorily 
employed for the purposes of these investigations. 

Samples of raw and cooked meat were treated with 100 cubic centi- 
meters of pepsin solution containing 10 cubic centimeters of 40 per 
cent formalin, kept at room temperature for twenty-four hours, then 
filtered, and the nitrogen determined in the imdigested residue. In 
connection with these tests the same meats were also dio-ested in 
the same way with 100 cubic centimeters of 0.33 per cent hydro- 
chloric acid without pepsin, to determine how much of the solvent 
action was due to the acid alone. The data of both these tests are 
given in Table 28. 



Table 28. — Tests of effect of formalin upon the action of 


the acid-pepsin solution. 




Doscription of sample. 


Digestion with acid-pepsin 
solution containing formalin. 


Digestion with acid a 


lone. 




Nitrogen in- 


Pro- 
portion 
of total 
nitro- 
gen in 

di- 
gested 
mate- 
rial. 


Nitrogen in- 


Pro- 
portion 
of total 
nitro- 
gen in 

di- 
gested 
mate- 
rial. 


Sample 
No. 


Total 
sample. 


Undi- 
gested 
por- 
tion. 


Di- 
gested 
por- 
tion. 


Total 
sample. 


Undi- 
gested 
por- 
tion. 


Di- 
gested 
por- 
tion. 

Gram. 

0. 0300 

.0325 


1107a 
1107b 


Lean beef round, raw 

do 


Gram. 

0.1185 

.1240 


Gram. 

0. 0661 

.0700 


Gram. 

0. 0524 

.0540 


Per ct. 
44.22 
43.55 


Gram. 

0. 1302 

.1366 


Gram. 

0. 1002 

.1041 


Per ct. 
23. 04 
23. 80 




Average 






.1213 


.0681 


.0532 


43.86 


.1334 


.1022 


.0312 


23.42 




Loan beef cooked in water 
do 




1116a 
lllfib 


. 14.53 
.1205 


.0962 
.0784 


.0491 
.0421 


33. 79 
34.94 


.1318 
.1299 


.1198 
.1184 


.0120 
.0115 


9.10 

8.85 




Average 






.1329 


.0873 


.0456 


34.37 


.1308 


.1191 


.0117 


8.98 




Lean Ix^ef round, raw 

do 

Average . 




1119a 
1119b 


.1144 

. 1178 


.0535 
. 0625 


.0609 
. 0553 


53.23 

46. 94 


.1288 
.1152 


.1046 
.0937 


.0242 
.0215 


18.79 
18.66 




.1161 


.0580 


.0581 


50.08 


.1220 


.0992 


.0228 


18.73 




Lean beef round, cooked 
i n wa tor 




1120a 


.1129 
.1245 


. 06l7 
. 0694 


.0512 
.0551 


45.35 
44.26 


.1212 
.1147 


.1062 
.1009 


.0150 
.0138 


12. 3S 


1120b 


. ..do... 


12.03 




Average 






i 




44.81 


.1180 


.1036 


.0144 


12.20 




Lean boef round, raw 

do 








1130a 
1130b 


.1449 
.1450 


.0899 
.0908 


. 0550 
. 0542 


37.96 
37.38 


. 1333 
.1348 


.1177 
.1180 


.0156 
.0168 


11.70 
12.40 




^Average 






.1450 


.0904 


.0546 


37.67 


. 1340 


.1178 


.0162 


12.08 




Loan beef round, cooked 

in water 

do 

A vcrage 




1131a 
1131b 


.1202 
. 1358 


.0719 
.0820 


.0483 
. 0538 


40.18 
39. 62 


. 1245 
.1228 


.1075 
.1052 


.0170 
.0176 


13.65 
14.33 




.1280 


.0769 


.0511 


39.90 


.1236 


.1063 


.0173 


13.99 









71 

It was evident from these tests that the acid alone had a very- 
appreciable influence upon the digestion of the meat, but that much 
more was due to the pepsin, since even in the presence of formalin 
the complete solution tligested on the average nearly three times the 
amount of protein that was dissolved by the acid alone. From a 
comparison of these results with those given in Table 27, which were 
obtained by digesting with the acid-pepsin solution mthout formalin 
at room temperature for twenty-four hours, it appeared that the 
presence of the formalin prevented approximately 55 per cent of the 
protein from being dissolved. 

It seemed probable that the more easily digestible material would 
be dissolved first, and that if the formalin were added after diirestion 
had continued for some time there would be little, if an}^, further 
action of the digestive solution during the time required for filtering. 
To test this h}^othesis two sets of experiments were made. In one 
set digestion was continued for exactly one hour, then 10 cubic centi- 
meters of formalin were added and the solution filtered as rapidly as 
possible. In the second set the digestion was conducted in exactly 
the same way, the formalin was added at the end of the hour, and the 
solution was then allowed to stand twenty-three hours before being 
filtered. The undigested residues were washed, and nitrogen deter- 
mined in them in the same way. The data of the tests are given in 
Table 29. 



Table 29. — Tests of effect of adding formalin after 


digestion had continued one 


hour. 




Description of sample. 


Digested 1 hour, added forma- 
lin, filtered at once. 


Digested 1 hour, added forma- 
lin, and kept at room tem- 
perature 23 hours before fil- 
tering. 


Sample 
No. 


Nitrogen in- 


Pro- 


Nitrogen in- 


Pro- 


Total 
sam- 
ple. 


Undi- 
gested 
por- 
tion. 


Di- 
gested 
por- 
tion. 


tion of 
total 
nitro- 
gen in 
digest- 
ed ma- 
terial. 


Total 
sam- 
ple. 


Undi- 
gested 
por- 
tion. 


Di- 
gested 
por- 
tion. 


por- 
tion of 

total 
nitro- 
gen in 
digest- 
ed ma- 
terial. 


1107a 
1107b 


Lean beef, round, raw 

do 


Gram. 

0. 1147 

.1189 


Gram. 

0. 0205 

.0194 


Gram. 

0.0942 

.0995 


Per ct. 
82.13 
83.68 


Gram. 

0. 1112 
.1084 
.1229 


Gram. 

0. 0243 
.0222 
.0247 


Gram. 

0. 0869 
.0862 
.0982 


Per ct. 
78.15 
79 52 


1107c 


do 


79 90 




Average 














.1168 


.0199 


.0968 


82.88 


.1142 


.0237 


0904 1 79 16 










1120a 

1120b 
1120e 


Lean beef, round, cooked 

in water 

do 

do 


.1091 
.1183 
.1258 


.0298 
.0312 
.0331 


.0793 
.0781 
.0927 


72.69 
73.63 
73.69 


.1230 
.1186 
.1156 


.0438 
. 0.325 
.0391 


.0792 ' 64 38 
.0861 72.60 
. 0765 1 66. 18 


1130a 
11.30b 
1130c 


Average 


.1177 1 .0313 


.0864 


73.41 


.1191 


.0385 


0806 1 67 67 


Lean beef, round, raw 

do 




.1253 
.1282 
.1502 


.0419 
.0437 
.0674 


.0834 
.0845 
.0828 


66.56 
65.88 
55.13 


.1483 
.1200 


.056.5 
.0421 


.0918 1 61.90 
0779 64. 91 


do 






Average 










.1346 . 0510 i . 0S.36 


62.11 


.1342 


.0493 


. 0849 6.3 5!fi 

















72 



Table 29. — Tests of effect of adding formaUn after digestion had eontintied one lionr- 

Coiiliiuic'd. 





Description of sample. 


Digested 1 hour, added forma- 
lin, filtered at once. 


Digested 1 hour, added forma- 
lin, and kept at room tem- 
perature 23 hours before fil- 
tering. 


Sample 

No. 


Nitrogen in- 


Pro- 
por- 
tion of 
total 
nitro- 
gen in 
digest- 
ed ma- 
terial. 


Nitrogen in— 


Pro- 


Total 
sam- 
ple. 


Undi- 
gested 
por- 
tion. 


Di- 
gested 
por- 
tion. 


Total 
sam- 
ple. 


Undi- 
gested 
por- 
tion. 


Di- 
gested 
por- 
tion. 


por- 
tion of 

total 
nitro- 
gen in 
digest- 
ed ma- 
terial. 


1131a 


Lean beef, round, cooked 
in water 


Oram. 

0. 1315 
.1292 
.1177 


Gram. 

0. 0392 
.0446 
.0379 


Gram. 

0. 0923 
.0846 
.0798 


Per ct. 
70.19 
65.48 
67.79 


Gram. 

0. 1317 
.1162 
.1350 


Gram. 

0. 0472 
.0312 
.0392 


Gram. 

0. 0845 
.0850 
.0958 


Per ct. 
64. 16 


1131b 


. ...do 


73. 15 


1131c 


do 

Average 


70.96 




.1261 


.0406 


.0856 


67.88 


.1276 


.0392 


.0884 


69.28 




Lean beef, round, cooked 
in water 




1148a 


. 1244 
.1207 
.1275 
.1229 
.128G 


.0300 
.0194 
. 0330 
.0306 


.0944 
.1013 
.0945 
. 0923 


75.88 
83.93 
74.12 
75.10 
7a 95 


.1247 
.1162 
.1170 
.1196 
.1341 
.1188 


.0298 
.0198 
.0218 
.0294 
.0353 
. 0313 


.0949 
.0964 
.0952 
.0902 
.0988 


76. 10 


1148b 


.do 


82.96 


1148c 
1148d 


do 

do 


81.37 
75.42 


1148e 


do 


. 0335 - 0951 


73 68 


1148f 


do 






. 0875 1 7a 65 




Average 
















.1248 


.0293 


.0955 


76.52 


. 1217 1 . 0279 


.0938 


77.07 













In some casos the results of these tests were not very satisfactory, 
but on the whole they seemed to warrant the conclusion that after 
digestion had continued for "an hour or more, formalin could be used 
quite effectively to check the action of the pepsin solution, so that 
there would be little or no further digestion during the filtering 
process. 

TESTS OF METHOD ADOPTED. 

When these facts had been established, a method for studying the 
relative ease or rapidity of digestion of meat cooked in different ways 
seemed available, and the following experiments were carried out: 

A large piece of lean beef round, from an animal about 5 years old, 
was divided into five similar portions, one of which (No. 1195) was 
not cooked, one (No. 1199) was cooked in water at 80° to 85° C. for two 
hours, one (No. 1200) was cooked in the same manner for five hoiu-s, 
one (No. 1197) was pan broiled, and one (No. 1198) was fried in hot 
lard. Each portion was then ground as finely as possible in the 
fresh condition (i. e., without drying) by passing it several tunes 
through a meat cutter, and the total nitrogen in a sample of each was 
determined by the Kjeldahl method. 

Several samples of each portion ..were digested as follows: Each 
sample (0.8 to 1.2 grams) was placed in a suitable flask, with 100 
cubic centimeters of a digestive solution containing 2.5 grams of 
pepsin in each liter of 0.33 per cent of hydrochloric acid, and the flask 
was then placed in a water bath and kept at a temperature of 38° to 
40° C. for a definite period. During the digestion the solution was 



73 



frequently stirred, and the lumps of meat were broken down. At th6 
end of the digestion period 10 cubic centimeters of a 40 per cent solu- 
tion of formalm was stirred into the digestive solution, and the latter 
was then filtered. The undigested residue was washed on the filter 
paper, and then dropped with the paper into a Kjeldahl flask and the 
nitrogen in it was determined. From this quantity and that of the 
nitrogen in the sample before digestion, the proportion digested was 
estimated. A comparison of these results for the samples cooked in 
different ways shows which was the more easily digested under the 
given conditions. 

Different lengths of digestion period were tried, namely, one, two, 
six, and twenty-four hours. The results obtained in digesting the 
samples twenty-four hours are given in Table 26 preceding. Those 
for the other three periods named are given in Table 30. 

Table 30. — EJfect of pepsin solvtion acting upon raic and cooked href for different 

lengths of time. 





Period of digestion and description of sample. 


Nitrogen— 


Propor- 
tion of 
total ni- 
trogen in 
digested 
material. 


Sample 
No. 


In total 
sample. 


In undi- 
gested 
portion. 


Indi- 
gested 
portion. 


119oa 


Digested for 1 hour. 
Lean beef round, raw 


Gram. 
0.1959 
.1013 
.1001 
.0875 
.1171 
.1312 


Gram. 
0.0700 
.0397 
.0368 
.0178 
.0426 
.0372 


Gram. 
0.1259 
.0613 
.0633 
.0697 
.0745 
.0940 


Per cent. 
64.27 


1195b 


do 


60.51 


1195c 


do 


63.24 


1195d 


. do . 


79.66 


1195e 


do 


63.62 


1195f 


do 


71.65 




Average 






.1222 


.0407 


.0815 


66.69 




Lean beef round, pan broiled 




1197a 


.0806 
.0689 
.0662 
.0646 
.0949 
.0780 


.0171 
.0160 
.0145 
.0121 
.0201 
.0181 


.0635 
.0529 
.0517 
.0.525 

.0748 
.0599 


78.78 


1197b 
1197c 
1197d 


do 

do 

do 


76.78 
78.10 
81.27 


1197e 


do . . . 


78.82 


1197f 


do . 


76.80 




A\'erage . - 






.0755 


.0163 


.0592 


78,41 




Lean beef round, fried in hot lard 

do 

do 

do 

do 

do ; 




1198a 
1198b 
1198c 
1198d 
11986 
1198t 


.0697 
.0686 
.0712 
.0742 
.0745 
.0727 


.0244 
.0247 
.0193 
.02,55 
.0243 
.0208 


.0453 
,0439 
.0517 
.0487 
.0502 
.0519 


64.99 
64.00 
72.61 
65.C)3 
67,. 38 
71.39 




Average 






.0718 


.0232 


.0486 


67,69 




Lean beef round, cooked in water 2 hours 




1199a 


.li58 
.09.56 
.0834 
.0733 
.0778 
.0847 


.0213 
.0165 
.0108 
.0089 
.0104 
.0076 


.0945 
.0791 
.0726 
.0644 
.0674 
.0771 


81.61 


1199b 
1199c 


do 

do 


82.74 
87.05 


1199d 
11998 
1199f 


do 

do 

do 

Average 

Lean beef round, cooked in water 5 hours 

do 

do 

do 

do 


87.86 
86. ()3 
91.03 




.0884 


.0126 


.0758 


&5.74 


1200a 
1200b 
1200c 
1200d 
1200G 


.0660 
.0860 
.0750 
.0924 
.08.53 
.0780 


.0153 
.0204 
.0190 
.0213 
.0201 
.0193 


.0507 
.0656 
.0560 
.0711 
.0652 
.a587 


76.82 
76.28 
74.67 
76,95 
76.43 


12001 


do 


75,26 




Average 






.0804 


.0192 


.0612 


76.12 









74 



Ta 



RLE 



30. — Effect of pepsin solution acting upon raiv and cooked, beef for different 
lengths of time — Continued. 





Period of digestion and description of .sample. 


Nitrogen— 


Propor- 
tion of 
total ni- 
trogen in 
digested 
material. 


Sample 
No. 


In total 
sample. 


In undi- 
gested 
portion. 


Indi- 
gested 
portion. 


1195a 


Digested for Z hours. 
Lean becl round, raw . ... 


Gram. 
0.1342 
.1022 
.0974 
.0855 
.1161 
.1158 


Gram. 
0.0404 
.0175 
.0218 
.0116 
.0254 
.0163 


Gram. 
0.0938 
.0847 
.0756 
.0739 
.0907 
.0995 


Per cent. 
69 90 


1195b 


do 


S9 88 


1195c 


do 


77 62 


1195d 


do 


80 43 


11956 


do 


78 12 


1195f 


do 


85 92 




Average 






.1085 


.0222 


.0863 


79 54 




Lean beel round , pan Ijroiled 




1197a 


.0714 
.0647 
.0682 
.0671 
.0670 


. .0084 
.0084 
.0081 
.0074 
.0083 


.0630 
.0563 
.0601 
.0597 
.0587 


88.24 


1197b 


do 


87 02 


1197c 


do 


88 12 


1197d 


do 


88 97 


1197e 


do 


87 61 




Average 






.0677 


.0081 


.0596 


88 04 




Lean beel round , Iried in hot lard 




1198a 


.0958 
.0741 
.0680 
.0844 
.0871 
.0757 


.0190 
.0154 
.0173 
.0180 
.0139 
.0112 


.0768 
.0587 
.0507 
.0664 
.0732 
.0645 


80.17 


1198b 


do 


79 22 


1198c 


do 


74 56 


1198d 


do 


78.67 


11986 


do 


84 04 


11981 


do 


85 20 










.0808 


.0158 


.0650 


80.45 








1199a 


.0872 
.0978 
.1067 
.0941 
.0911 
.0788 


.0065 
.0077 
.0086 
.0062 
.0048 
.0044 


.0805 
.0901 
.0981 
.0879 
.0863 
.0744 


92 32 


1199b 


do 


92.13 


1199c 


do 


91.94 


1199d 


do 


93.41 


1199e 


....do 


94.73 


11991 


do 


94.42 




Average 




- 


.0926 


^ .0064 


.0862 


93.09 




Lean beef round, cooked in water 5 hours 




1200a 


.0702 
.0817 
.0749 
.0744 
.0750 
.0898 


.0152 
.0140 
.0134 
.0132 
.0132 
.0162 


.0550 
.0667 
.0515 
.0612 
.0618 
.0736 


78.35 


1200b 


do 


82.86 


1200c 
1200d 
12006 
12001 


do 

do 

do 

do 

Average 


82.11 
82.26 
82.40 
81.96 




.077? 


.0142 


.0635 


81.73 


119Sa 


.1044 
.0784 
.0586 
.1110 
.0847 
.1050 


.0142 
.0060 
.0059 
.0057 
.0105 
.0090 


.0902 
.0724 
.0527 
.1053 
.0742 
.0968 


80.40 


1195b 
1195c 
1195d 
11956 
11951 


do 

do 

do 

do 

do 

Average 

Lean beef round, pan Ijroiled . . 


92.35 
89.93 
94.86 
87.60 
91.49 




.0905 


.0086 


.0819 


90.50 


1197a 


.0689 
.0764 
.0732 
.0861 
.0673 
.0821 


.0047 
.0055 
.0059 
.0062 
.0028 
.0073 


.0042 
.0709 
.0673 
0799 
.0645 
.0748 


93.18 


1197b 
1197c 
1197d 
11976 
11971 


do 

do 

do 

do 

do 


92.80 
91.94 
92.80 
95.84 
91.11 




.0757 


.0054 


.0703 


92.87 


iisaa 


.0729 
.0796 
.0792 
.0739 
.0620 
.0731 


.0071 
.0091 
.0062 
.0052 
.0044 
.0070 


.0658 
.07a'i 
.0730 
.0687 
.0576 
.0661 


90.26 


1198b 


.do 


88.. 57 


1198c 


do 


92.17 


1198d 


do 


92.96 


11986 


do 


92.90 


11981 


. ..do 


90.42 




Average 






.0734 


.0065 


.0669 


91.14 









75 



Table 30. — Effect of pepsin solution acting upon raw and cooked beef for different/ 

lengths of time — Continued. 



Sample 

No. 



1199a 
1199b 
1199c 
1199d 
1199e 
1199f 



1200a 
12001) 
1200c 
1200d 
1200e 
1200f 



Period of digestion and description of sample. 



Digested for 6 ftour.s— Continued. 

Lean beef round, cooked in water 2 hours. 

do 

....do 

....do 

....do 

....do 



Average . 



Lean beef round, cooked in water 5 hours. 
do 



.do. 
.do. 
.do. 
.do. 



Average . 





Nitrogen- 




Propor- 
tion of 








In total 
sample. 


In undi- 


In di- 


total ni- 


gested 
portion. 


gested 
portion. 


trogen in 
digested 
material. 


Gram. 


Gram. 


Gram. 


Per cent. 


0.0825 


0.0029 


0.0796 


96.48 


. 1057 


.0047 


.1012 


95.74 


.0962 


.0037 


.0925 


96.15 


0988 


.0038 


.0950 


96.15 


.0891 


.0028 


.0863 


96.86 


.0869 


.0027 


.0842 


96.89 


.0932 


.0034 


.0898 


96.35 


.0660 


.0030 


.0630 


95.45 


.07(55 


.0029 


.0730 


96.21 


.0662 


.0031 


.0631 


95.32 


.0725 


.0034 


.0691 


95.31 


.0814 


.0045 


.0769 


94.47 


.0738 


.0034 


.0704 


95.39 


.0727 


.0034 


.0693 


95.32 



The averages of the results obtained in the individual tests, includ- 
ing those given in Table 26 as well as those in the table above, are 
summarized in Table 31. 

Table 31. — Summary of results of artificial digestion experiments with raw and cooked 

beef. ■ 



Sample 
No. 



1195 
1197 
1198 
1199 
1200 



Description of sample. 



Coefficients of digestiliility of meats 
treated with pepsin solution for — 



1 hour. 2 hours. 6 hours. 24 hours 



Lean beef, round, raw 

Lean beef, round, pan broiled 

Lean beef, round, fried in hot lard 

Lean beef cooked in water 2 hours 

Lean beef, round, cooked in water 5 hours 



66.69 
78.41 
67. 69 
85.74 
76.12 



79.54 
88.04 
80. 45 
93.09 
81.73 



90.50 
92.87 
9L14 
96.35 
95.32 



97.31 
96.49 
95.07 
97.44 
96. 95 



No conclusions regarding the relative ease of digestion of the dif- 
ferent samples are drawn from the above data, because they are 
too few. The particular information that was derived from these 
tests was that the method developed seemed admirably adapted for 
a study of the question. The variations in results obtained in dupli- 
cate tests were in some instances rather wider than is desirable, 
but it was believed that with more skill in riianipulation, and with 
such refinement in technic[ue as would come with practice, more 
uniform results could be obtained. 

It will be noticed that the above tests were made with meat in 
the fresh condition, ground as small as possible with a meat cutter 
or sausage mill; whereas in previous tests the meat had been dried 
and very finely ground before digestion. A test was made with the 
uncooked meat used in the above experiment, to determine whether 
the same results could be obtained with the fresh as with the dried 
material. Part of the raw meat was dried and ground as usual, and 



76 

samples were digested in the same way as the fresh samples were. 
The averao;es of the results obtained in the individual tests are com- 
pared in Table 32. 

Table 32. — Comparison of results ivith/rcsh and dried samples of meal. 



Sainple 


Kcscription of sample. 


Coefficients obtained by digestion for— 


No. 


1 hour. 


2 hours. 


6 hours. 


24 hours. 


1195 


Lean beef, round, raw, fresh substance 


66. 69 
65. 57 


79.54 
75.29 


90.50 
89.14 


97.31 


1195 


Lean beef, round, raw, dried substance 


97. 49 









The advantage seemed to be in favor of the digestion of the fresh 
substance. Accordingly in subsequent experiments this method was 
followed, in general, in order to avoid the drying. and grinding of the 
material. 

DETAILS OF EXPERIMENTS ON THE EASE OF DIGESTION OF 

PROTEIN. 

As previously stated, 92 experiments were made with different 
kinds and cuts of meat cooked in diflPerent ways. Of these, 67 were 
with beef, 5 with mutton, and 20 with ^)ork. In some cases the 
meats used in these experiments were the same as those in the natu- 
ral digestion experiments, and in other cases different kinds of meats 
were used for the artificial digestion tests. 

The method employed was that explained on preceding pages, 
except that the strength of the acid-pepsin solution was altered. In 
all the experiments hereafter reported the digestive solution con- 
tained 1.25 grams of pepsin, instead of 2.5 grams, in each liter of 
0.33 per cent hydrochloric acid. In all other respects the method 
was as outlined above (p. 72). 

In several cases a large piece of some particular ^'cut" of meat was 
divided into several similar portions, one of which was not cooked 
and the others were cooked in different ways. In such cases there 
is opportunity for comparing results with raw and cooked meats that 
before cooking were as nearly alike as possible. In other instances 
similar cuts of meat from difl'erent animals were used, some of wliich 
were not cooked , wliile the remainder were all cooked in the same way. 

Several of the experiments were made with different "cuts" of 
meat from the same animal, all cooked in the same way, to deter- 
mine whether there is an}^ difference in the ease of digestion of meat 
from different parts of the same carcass. 

Both fat meats and lean meats were used, to ascertain how they 
compare in respect to ease of digestion. In order that the relative 
fatness of the meats might be definitely known samples were analyzed 
in the usual way. The data regarding the composition of these 
samples are given in Table 33. 



n't 
I I 



Table 33. — Composition of vieats used in artificial digestion experiments here reported. 



Lab- 
ora- 
tory 
No. 


Kind of meat. 


Used in 

e.xperi- 

ment 

No.— 


Water. 


Protein 
(NX6.25). 


Fat. 


Ash. 


1390 


Beef round, cooked in water 


43 
48 
55 
70 
94 
95 
41 
46 
42 
47 
44 
49 
45 
50 
51 
6fi 
81 
82 
83 
84 
85 
94 
95 
96 
81 
82 
83 
84 
85 
91 
91 
92 
92 
93 
93 
94 
95 
96 
97 
97 
97 
52 
67 
53 
68 
54 
69 
56 
57 
58 
59 
60 
71 
72 
73 
74 
75 
76 
77 
78 
79 
80 
86 
87 
88 
63 
71 
72 
73 
74 
75 
76 
77 
78 
79 
80 
86 
87 
88 
89 


Per cent. 
61.71 
59.52 
.53. 12 
53. 66 
61.79 
62.78 
76.84 
75.64 
68.86 
59.02 
60.54 
48. 67 
57.92 
55.87 
51.16 
49.43 
49.89 
48.16 
35. 77 
46.09 
48.54 
51.46 
46.43 
60.00 
47.51 
40.49 
32.94 
62.89 
56.20 
35. 12 
49. 63 
28.02 
42.45 
54.53 
49.88 
45.74 
33.30 
54.83 
43.61 
55.11 
44.43 
60.14 
65.00 
62.96 
58.19 
51.80 
51.29 
42.82 
40.82 
61.09 
38.27 
47.77 
61.61 
54.48 
■ 49. 58 
52.54 
51.07 
54.80 
52.73 
35.04 
55. 88 
63.77 
58.45 
57. 76 
58.29 
50.49 
53.37 
50. 45 
51.46 
48.17 
41.20 
51.61 
51.22 
49.38 
55.13 
54.36 
53. 62 
56.05 
59.12 
53.57 


Per cent. 
36. 20 
34. 20 
30.08 
30.83 
33.84 
33.75 
20.75 
21.17 
28.18 
34.27 
32. 54 
41.09 
35.66 
36.34 
22.78 
18.07 
16.11 
14. 35 
10. 56 
13.61 
14.82 
14.81 
12. 60 
17.82 
20.16 
19.73 
15. 78 
17.89 
18. 95 
19.50 
21.95 
21.94 
20.97 
23.55 
20.56 
18.22 
16.34 
19. 26 
23.63 
24. 64 
20.04 
26.30 
24.88 
22.23 
18. 15 
20.59 
19.16 
19.70 
16.85 
22. 15 
16.17 
18.28 
15.76 
13. 64 
13.90 
14.13 
14. .50 
14.00 
13.96 
14.76 
14.95 
16.35 
16.10 
15.50 
17.41 
17.32 
23.00 
16.76 
21.78 
21.42 
29.15 
18.99 
18.95 
23.63 
23.44 
23. 52 
24.77 
26.52 
23.47 
26.40 


Per cent. 
1.99 
6.19 
16.34 
16.05 
3.27 
2.65 
1.78 
2.42 
•2.15 
6.42 
5.95 
9.77 
6.05 
7.60 
26.20 
32.53 
33.77 
36.96 
53.29 
39.58 
35.90 
33. 62 
40.62 
21.78 
32.08 
39.60 
.51.32 
18.34 
24.33 
44.92 
28.26 
49. 60 . 
36.85 
21.61 
28.06 
35.49 
50.04 
25. 16 
30.67 
18.21 
34.09 
13.60 
10.07 
14.58 
23.59 
27.62 
29.67 
37.05 
42.44 
16.60 
45. 42 
33.69 
21.85 
31.61 
35. 94 
33.10 
33.82 
30.58 
33. 07 
49.49 
29. 05 
19.48 
24.84 
26.50 
24.01 
31.69 
23. ,38 
31.92 
26.51 
29.80 
29.63 
28.78 
29.39 
26. 36 
2). 20 
21.82 
21.04 
17.09 
17.36 
19.73 


Per cent. 
0.93 


1395 


.do 


1.03 


1403 


do 


.81 


146.5 


do 


.93 


1634 


.do 


1.04 


1635 


do . 


1.01 


1388 


Beef round, raw 


1.09 


1393 


.do 


1.16 


1389 


Beef round, pan broiled 


1.32 


1394 


do . . 


1..50 


1391 


Beef round, fried in lard 


1.40 


1396 


do 


1.62 


1392 


Beef round, roasted 


1..37 


1397 


.do 


1..33 


1399 


Beef ribs, cooked in water 


.82 


1461 


.do 


.67 


1520 


Beef rilis, raw 


.72 


1521 


do 


.69 


1522 


.do 


.52 


1535 


.do 


.67 


1541 


do 


.73 


1611 


.do 


.72 


1612 


.do 


.61 


1613 


do 


.86 


1537 


Beef ribs, roasted 


.91 


1536 


..do 


.91 


1538 


do 


.72 


1539 


do 


.80 


1540 


.do 


.89 


1587 


..do 


.79 


1588 


.do 


.95 


1589 


.do 


.87 


1590 


....do 


.82 


1591 


.do 


.95 


1595 


.do 


2.37 


1615 


..do 


.92 


1614 


....do 


.74 


1616 


.do 


.97 


1617 


.do 


2.34 


1561 


..do 


2.55 


1525 


.do 


1.93 


1400 


Beef leg, cooked in water 


.74 


1462 


do 


.89 


1401 


Beef neck, cooked in water 


.91 


1463 


.do 


.70 


1402 


Beef flank, cooked in water 


.71 


1464 


.do 


.63 


1424 




.77 


1425 


Mutton, flank, cooked in water 


.56 


1426 


Mutton, leg, cooked in water 


.99 


1427 


Mutton, loin 


.55 


1428 


Mutton, ril IS . . ; 


.67 


1482 


Pork, fresh ham, raw 


.83 


1485 


....do 


.66 


1487 


do 


.72 


1488 


. ..do 


.74 


1490 


...do 


.73 


1492 


do 


.70 


1505 


..do 


.78 


1507 


....do 


.82 


1510 


do 


.80 


1515 


. ..do...' 


.93 


1542 


do 


.85 


1543 


do 


.77 


1544 


..do 


.82 


1432 


Pork, fresh ham, cooked in water 


.66 


1483 


Pork, fresh ham, roasted 


1.02 


1484 


do 


.79 


I486 


do 


.88 


1489 


....do 


.91 


1491 


do 


.99 


1493 


do 


.87 


1.504 


do 


.96 


1506 


do.... 


1.08 


1511 


do 


1.09 


1514 


do 


.88 


1545 


do 


1.00 


1558 
1559 
1573 


do 

do 

do 


1.08 
1.02 
1.01 



78 



Table 33. — Composition of vieals used in artijicial digestion experiments here reported- 
Continued. 



Lab- 
ora- 
tory 
No. 



1574 
1575 
1580 
1430 
1431 
1433 
1434 



Kind of meat. 



Pork, fresh ham, roasted 

do 

do 

Pork, beUy, cooked in water 

Pork, middle cut, cooked in water 
Pork, shoulder, cooked in water. 
Pork, back, cooked in water 



Used 
experi- 
ment 
No.— 



n 



89 
90 
90 
61 
02 
64 
65 



Water. 



Per cent. 
55.43 
51.40 
61.71 
41.32 
44.61 
60.68 
52.96 



Protein 

(NX6.25). 



Per cent. 
24.52 
25.88 
19.33 
15.52 
17.22 
21.59 
21.14 



Fat. 



Percent. 
19.44 
22. 46 
18.27 
42.95 
37.82 
17.31 
25.47 



Ash. 



Per cent. 
1.05 
.99 
.74 
..52 
.53 
.81 
.82 



EXPERIMENTS WITH BEEF. 



A description of the kinds and cuts of beef and the methods of 
cooking is here given. 

Experiments Nos. 7 to 11 were made with a piece of beef round, from an animal 
about 2^ years old, which was divided into five similar portions. No. 1202 was not 
cooked, No. 1203 was pan broiled, No. 1204 was fried in hot lard, No. 1205 was cooked 
in water at 80° to 85° for two hours, and No. 1200 was cooked in the same manner for 
five hours. 

Experiments Nos. 12 to 16 were made with a piese of beef round, from an animal 
about 3 years old, which was divided into five similar portions. No. 1210 was not cool^ed, 
No. 1215 was pan broiled. No. 1219 was fried in lard, No. 1211 was cooked in water at 
80° to 85° for two hours, and No. 1210 was cooked in the same manner for five liours. 

Experiments Nos. 17 to 21 were made with a piece of beef round, from an animal 
about 3 years old, which was divided into five similar portions. No. 1235 was not 
cooked, No. 1238 was pan broiled, No. 1241 was fried in hot lard, No. 1242 was cooked 
in water at 80° to 85° for one hour, and No. 1243 was similarly cooked for five hours. 

Experiment No. 22 was made with a piece of very fat beef sirloin, No. 1279, from an 
animal about 2| years old. The meat was broiled in a gas oven until somewhat 
underdone. 

Experiment No. 23 was made with a piece of very fat beef sirloin, No. 1280, from 
an animal about If years old. The meat was broiled in a gas oven until well done. 

Experiment No. 24 was made with a piece of very fat beef sirloin. No. 1281, from 
an animal about 2j years old. It was broiled in a gas oven until somewhat underdone. 

Experiment No. 25 was made with a piece of very fat beef sirloin, No. 1282, from 
an animal about 24 years old. The meat was broiled in a gas oven until somewhat 
underdone. 

Experiment No. 26 was made with a i)iece of veiy fat beef sirloin. No. 1283, from 
an animal about 2^ years old. The meat was broiled in a gas oven until somewhat 
underdone. 

Experiments Nos. 27 and 28 were made with a piece of very fat beef shoulder from 
an animal about 2i years old. The meat was obtained fifteen days after the animal 
was slaughtered. The piece was cut into two portions, one of which (No. 1300) was 
not cooked and the other (No. 1287) was cooked in water at 80° to 85° for two hours. 

Experiment No. 29 was made with a piece of very fat beef sirloin. No. 1302, from 
an animal about 2 years old. The meat was obtained eighteen days after slaughtering 
and was not cooked. 

Experiment No. 30 was made with a i)ii'ce of very fat beef sirloin, No. 1303, from 
an animal about 3 years old. The meat was obtained eighteen days after slaughtering 
and was not cooked. 



79 

Experiment No. 31 was made with a piece of very fat beef sirloin, No. 1305, from' 
an animal about 2 years old. The meat was obtained eighteen days after slaughtering 
and was not cooked. 

Experiment No. 32 was made with a piece of very fat beef sirloin, No. 1306, from 
an animal about 3 years old. The meat was obtained eighteen days after slaughtering 
and was broiled in a gas oven. 

Experiment No. 33 was made with a piece of very fat beef sirloin, No. 1307, from 
an animal about 3 years old. The meat was obtained eighteen days after slaughtering 
and was broiled in a gas oven. 

Experiment No. 34 was made with a piece of very fat beef sirloin. No. 1309, from 
an animal about 2 years old. The meat was obtained twenty-one days after slaugh- 
tering and was broiled in a gas oven. The samples were digested nine days after the 
meat was cooked. 

Experiments Nos. 35 and 36 were made with a piece of lean beef round from an animal 
about 3 years old. One portion of the cut. No. 1314, was not cooked; the other 
portion, No. 1313, was pan broiled until well done. 

Experiments Nos. 37 and 38 were made with a piece of lean beef round from an animal 
about 3 years old. One portion of the cut. No. 1331, was not cooked; the other 
portion, No. 1330, was fried in hot lard. 

Experiments Nos. 39 and 40 were made with a piece of lean beef round from an animal 
about 2 years old. One portion of the cut. No. 1348, was not cooked; the other 
portion, No. 1347, was roasted in a gas oven until well done. 

Eperiments Nos. 41 to 45 were made with a piece of lean beef round, from an animal 
about 2^ years old, which was divided into five portions. No. 1388 was not cooked, 
No. 1389 was pan broiled until well done, and No. 1390 was kept in lioiling water for 
ten minutes and the temperature of the water was then reduced to 85° and cooking was 
continued for two hours at 80° to 85°. The meat was well done. No. 1391 was fried in 
hot lard until well done. No. 1392 was roasted in a gas oven. 

Experiments Nos. 46 to 50 were made with a piece of lean beef round, from an 
animal about 3 years old, which was divided into five portions. No. 1393 was 
not cooked, No. 1394 was pan broiled until well done. No. 1395 was kept in boiling 
water for ten minutes then cooked for two hours in water at 80° to 85°, No. 1396 was 
fried in hot lard until well done, and No. 1397 was roasted in a gas oven. 

Experiments Nos. 51 to 55 were made with different cuts of beef from the same 
animal, which was about 3 years old at the time of slaughtering. No. 1399 was 
a very fat first cut of ribs, known locally as "rib roast;" No. 1400 was a moderately 
fat leg piece, known locally as "soup bone;" No. 1401 was a second cut of the neck, 
moderately fat, known as a "boiling piece:" No. 1402 was a very fat piece of the 
flank bone, known locally as the "flank boiling piece;" No. 1403 was a rather fat 
piece of ])eef round. In each case the meat was cooked by placing it in boiling water, 
the temperature of which was maintained at 100° for ten minutes, then j-educed to 
85° and kept at 80° to 85° for two hours. 

Experiments Nos. 66 to 70 were made with different cuts of beef from the same 
animal, which was about 2 years old at the time of slaughtering. No. 1461 was a 
first cut of the ribs. No. 1462 was a leg piece. No. 1463 was a second cut of the neck, 
No. 1464 was a flank piece, and No. 1465 was a piece of the round. Each cut was 
cooked in water which was kept l)oiling for ten minutes and then at 80° to 85° for 
two hours. 

Experiment No. 81 was made with beef ribs. One portion (1520) was uncooked 
and the other jiortion (1537) was roasted. 

Experiment No. 82 was made with beef ribs. One portion (1521) was uncooked 
and the other portion (1536) was roasted. 

Exi^eriment No. 83 was made with beef ribs. One portion (1522) was not cooked 
and the other pf)rtion (1538) was roasted. 

4663— Bull. 193—07 6 



80 

Experiment No. 84 was made with beef ribs. One portion (1535) was uncooked 
and the other portion (1539) was roasted. 

Experiment No. 85 was made with beef ribs. One portion (1541) was uncooked 
and the other (1540) was roasted. 

Experiment No. 91 was made with two pieces (1587 and 1588) of roasted beef ribs, 
very fat. 

Experiment No. 92 was made with two pieces (1589 and 1590) of roasted beef ribs, 
very fat. 

Experiment No. 98 was made with two pieces (1591 and 1595) of roasted beef ribs, 
very fat. 

Experiment No. 94 was made with a cut of beef ribs, one portion of which (Kill) 
was uncooked and the other portion (1615) was roasted. 

Experiment No. 95 was made with a cut of beef ribs, one portion of which (1612) 
was uncooked and the other portion (1614) was roasted. 

Experiment No. 96 was made with a cut of beef ribs, one portion of which (1613) 
was uncooked and the other portion (1616) was roasted. 

Experiment No. 97 was made with three cuts (1617, 1561, and 1525) of beef ribs 
roasted. 

Experiment No. 98 was made with two similar portions of the same piece of beef round 
cooked in water that was kept boiling for ten minutes and then at 80° to 85° C. for 
two hours. One portion (1634) was ground twice in a sausage mill and the other 
portion (1635) was cut into quarter-inch cubes. The purpose of this experiment was 
to afford some indication regarding effect of thorongh mastication upon the ease of 
digestion. 

The data regarding the artificial digestion of the protein of the above 
samples are given in Table 35. In a very few cases the figures there 
given represent the data from individual tests, but in the large 
majority of cases they are the averages for several tests with the same 
sample, the number included in the average ranging from 2 to 5, as 
shown in one of the columns. For example, in the case of the first 
item in the table, with sample No. 1202 digested for one hour, four 
tests, a, h, c, and d, were made, the data of which are given in Table 34. 

Table 34. — Results of individual tests on digestion of raw beef round. 





Nitrogen in- 


Proportion 

of total 

nitrogen 

in digested 

material. 


Sample No. 


Total 
sample. 


Undigested 
portion. 


Digested 
portion. 


1202a 


Gram. 

0.0715 

.0730 

.1081 

. 0728 


Gram. 

0. 0045 

.0045 

.0103 

.0058 


Gram. 

0. 0670 

.0685 

.0978 

.0670 


Per cent. 
94 


12026 


94 


1202f 


90 


1202(f 


92 






Average 


.0814 


.0063 


.0751 


92 







The average of the quantities of nitrogen in the four portions of the 
sample that were weighed for digestion was 0.0814 gram; that in the 
undigested residue, 0.0063 gram, and in the digested portion, 0.0751 
gram. According to these figures 92 per cent, on the average, of the 
nitrogen of the meat was present in the protein that was digested. 
Among the individual tests the proportion ranged from 90 to 94 per 



81 

cent. These latter figures are given in the last two columns of Table 
35 to show the variations in results of the individual tests from which 
the average figures were derived. 

Table 35. — Results obtained in artificial digestion of samples of different cuts of beef, 

raw and cooked in different ways. 



Description of sample. 



Digested 1 hour. 

Experiments Nos. 7-11: 
Beef round — 

Raw 

Pan broiled , 

Fried in hot lard 

Cooked in water 2 hours 

Cooked in water 5 hours 

Experiments Nos. 12-16: 
Beef round, lean — 

Raw , 

Cooked in water 2 hours 

Cooked in water 5 hours 

Pan broiled 

Fried in hot lard 

Experiments Nos. 17-21: 
Beef round, lean — 

Raw 

Pan broiled 

Fried in hot lard 

Cooked in water 1 hour 

Cooked in water 5 hours 

Experiments Nos. 22-26: 

Beef sirloin, very fat, broiled, un- 
derdone 

Beef sirloin, very fat, broiled, well 

done 

Beef sirloin, very fat, broiled, un- 
derdone 

....do 

do 



Average of 5. 



Experiments Nos. 27-28: 

Beef shoulder, very fat, cooked in 

water 2 hours 

Beef shoulder, moderately fat, raw 
Experiments Nos. 29-31: 

Beef sirloin, very fat, raw 

Do 

Do 



Average of 3. 



Experiments Nos. 32-34: 

Beef sirloin, very fat, broiled. 

Do 

Do 



Average of 3. 



Experiments Nos. .35-36: 

Beef round, lean, raw 

Beef round, lean, pan broiled, well 

done 

Experiments Nos. 37-38: 

Beef round, lean, raw 

Beef round, lean, fried in hot lard, 

well done 

Experiments Nos. 39-40: 

Beef round, lean, raw 

Beef round, lean, roasted, well done 



Num- 
ber of 
tests 
in av- 
erage. 



Nitrogen in- 



Meat. 



Gram. 

0. 0814 
.0720 
.0757 
.0617 
.0767 



.0911 
.0994 
.0943 
.0644 
.0947 



.0950 
.0546 
.0993 
. 0933 
.0748 



.0490 

.0591 

.0412 
.0498 
.0980 



Undi- 
gested 
por- 
tion. 



.0594 



.0890 
.0970 

. 0757 
.0476 
.0612 



.0615 



.0663 
.0918 

.0877 



.0819 



.1079 

.0827 

.0873 

.1030 

.0951 
.1109 



Gram. 

0.0063 
.0178 
.0205 
.0305 
.0292 



.0127 
.0155 
.0112 
.0144 
.0237 



.0100 
.0090 
.0218 
.0145 
.0136 



.0078 

.0139 

.0109 
.0092 
.0225 



Digest- 
ed por- 
tion. 



.0129 



Gram. 

0. 0751 
.0542 
.0552 
.0312 
.0475 



.0784 
.0839 
.0831 
.0500 
.0710 



.0850 
.0456 
.0775 
.0788 
.0612 



.0412 

.0452 

.0303 
.0406 
.0755 



Proportion of total ni- 
trogen in digested 
portion. 



Aver- 
age. 



.0466 



.0187 
.0158 

.0159 
.0095 
.0108 



.0121 



.0135 
. 0186 
.0146 



.0156 



.0125 

. 0163 

.0142 

.0221 

.0149 
. 01.33 



.0703 
.0812 

.0598 
. 0.381 
.0504 



.0494 



.0528 
.0732 
.0731 



0664 



.0954 

.0664 

.0731 

.0809 

.0802 
.0976 



Per ct. 
92.26 
75.28 
72.92 
50; 57 
61.93 



86.06 
84.41 
88.12 
77.64 
74.97 



89.47 
83.52 
78.05 
84.46 
81.82 



84.08 

76.48 

73. 54 
81.53 
77.04 



Mini- 
mum. 



78.53 



Per ct. 
90.44 
74.72 
72.57 
48.13 
58.65 



85.57 

78. 76 
85.47 
75.93 
72.28 



87.52 
80.48 
75.75 
81.85 
79.28 



82.93 

68.09 

72.28 
81.18 
76. 19 



78.99 
83.71 

79.00 
80.04 
82.35 



80.46 



79.64 
79.74 
83.35 



80.91 



88.42 
80.29 
83.73 

78. 54 

84.33 
88.01 



78.37 
82. 30 

77.58 
78.72 
82.16 



78.22 
78.24 
82.38 



87.10 

78.73 

S3. 10 

77.32 

82.10 
87. 53 



Maxi- 
mum. 



Per ct. 
93.88 
76.05 
73.31 
53.46 
67.52 



86.40 
89.56 
93.86 
79.03 
76.39 



91.38 
86.73 
80.72 
88.15 
84.96 



84.99 

85.83 

74.69 
81.99 
78.63 



79.37 
85.04 

80.00 
80.98 
82.75 



81.54 
80.97 
84.30 



89.40 
81.72 
84.21 
79.47 

86.03 

88.52 



82 

Table 35. — Results obtained in artificial dic/estion of samples of different cuts of beef, 
raw and cooked in different ways — Continued. 



Labo- 
ra- 
tory 
No. 



Description of sample. 



1388 
1389 
1390 

1391 
1392 



1393 
1394 
1395 
1396 
1397 



1399 
1400 
1401 

1402 
1403 



1461 
1462 
1463 
1464 
1465 



1202 
1203 
1204 
1205 
1206 



1210 
1211 
1212 
1215 
1219 



1235 
1238 
1241 
1242 
1243 



1279 

1280 

1281 

1282 
1283 



1287 
1300 



Digested 1 Ao«r— Continued. 

Experiments Nos. 41-45: 
Beef round, lean- 
Raw 

Pan broiled 

Cooked in water 2 hours, well 

done 

Fried in hot lard, well done 

Roasted, well done 

Experiments Nos. 46-50: 
Beef round, lean- 
Raw 

Pan liroiled 

Cooked in water 2 hours 

Fried in hot lard 

Roasted 

Experiments Nos. 51-55: 

Beef, different outs, all cooked in 
water 2 hours — 

First cut ribs, very fat 

Leg bone, moderately fat 

Second cut neck, moderately 

fat 

Flank, very fat 

Roimd, rather fat 

Experiments Nos. 66-70: 

Beef, difTerent cuts, all cooked in 
water 2 hours — 

First cut ribs, underdone 

Leg bone 

Second cut, neck 

Flank, well done 

Round, well done 



Num- 
ber of 
tests 
in av- 
erage. 



Nitrogen in- 



Meat. 



Digested 2 hours. 

Experiments Nos. 7-11: 
Beef round — 

Raw 

Pan broiled 

Fried in hot lard 

Cooked in water 2 hours. . 

Cooked in waters hours.. 
Experiments Nos. 12-16: 
Beef round, lean- 
Raw 

Cooked in water 2 hours. 

Cooked in water 5 hours. 

Pan broiled 

Fried in hot lard 

Experiments Nos. 17-21: 
Beef round, lean — 

Raw 

Pan broiled 

Fried in hot lard 

Cooked in water 1 hour.. 

Cooked in water 5 hours. 



Experiments Nos. 22-26: 

Beef sirloin, very fat, broiled, 

underdone 

Beef sirloin, very fat, broiled, well 

done 

Beef sirloin, very fat, broiled, 

underdone 

Do 

Do 



Average of 5 . 



Experiments Nos. 27-28: 

Beof shoulder, very fat, cooked in 

water 2 hf)urs 

Beef shoulder, moderately fat, raw 



Undi- 
gested 
por- 
tion. 



Gram. 

0.0913 

.0897 

r 

.0930 
.0738 
.0932 



.0872 
.0827 
.0896 
. 1031 
.0962 



.0722 
.0750 

.0684 
.0670 
.0942 



.0608 
.0730 
.0680 
.0560 
.1035 



.0887 
.0770 
.0725 
. 0699 
.0660 



.0848 
. 1083 
.0851 
.0626 
.0982 



.0970 
.0588 
.0803 
.1069 
.0988 



Digest- 
ed por- 
tion. 



Gram. Gram. 

0. 0098 0. 0815 

.0134 .0763 



. 0517 

.0630 

. 0604 
.0488 
.1123 



.0672 



.0802 
.1015 



.0179 
.0178 
.0161 



.0148 
.0187 
.0249 
.0240 
.0138 



. 0161 
.0246 

.0172 
.0222 
.0186 



. 01.32 
.0157 
.0201 
.0180 
.0178 



.0052 
.0135 
.0097 
.0186 
.0167 



.0076 
.0084 
.0077 
.0079 
.0177 



.0083 
. 0056 
. 0076 
.008,5 
.0098 



.0072 

. 0095 

.0118 
. 0061 
.0198 



.0109 



.0123 
.0141 



.0751 
.0560 
'. 0771 



.0724 
.0640 
.0647 
.0791 
.0824 



. 0561 
.0504 

.0512 
.0448 
. 0757 



. 0476 
.0573 
.0479 
. 0380 
.0857 



.0835 
.0035 
. 0628 
.0513 
.0493 



.0772 
.0999 
.0774 
. 0547 
.0805 



.0887 
.0532 
.0727 
.0984 
.0890 



Proportion of total ni- 
trogen in digested 
portion. 



. 0445 

. 05,35 

. 0486 
.0427 
.0925 



Aver- 
age. 



.0564 



. 0679 
.0874 



Mini- 
mum. 



Per ct. 
89.27 
85. 06 

80.75 
75. 88 
82.73 



83.03 
77.39 
72.21 
76.72 
85.65 



77. 70 
67.20 

74.8,5 
66.87 
80.36 



78.29 
78.49 
70.44 
67. 86 
82.80 



94.14 
82.47 
86. 62 
73.39 
74.70 



91.04 
92.24 
90. 95 

87.38 
81.98 



91.44 
90.48 
90.54 
92.05 
90.08 



Per ct. 

88.17 
83.52 

78.44 
75. 06 
81.90 



81.78 
76.36 
71.12 
76.17 
84.91 



77.27 
66.58 

73.59 
64.53 

78.78 



86.07 

84.92 

80. 46 
87.50 
82.37 



Maxi- 
mum. 



78.28 



66.53 
82.25 



93. 83 
81.27 
85.93 
70.20 
73. 43 



90.83 
91.89 

88.47 
86. 10 
78.14 



91.11 
8.5. 94 
89.21 
89.00 
85.77 



Per ct. 
W. 31 
86.60 

81.89 
77. 05 
84.90 



84.72 
78.34 
7.3. 76 
77. 35 
86.17 



78.61 
67.64 

75. 84 
68.74 
81.07 



85.81 

83.19 

79.70 
86.24 
80.31 



84.26 



84.66 
86.11 



83.18 
&5.21 



78.55 



69.34 
83.68 



94.50 

85. OS 
87.27 
75.54 
75. 69 



91.29 
92.93 
93. 54 

88.95 
84.03 



91.91 
92.98 
92. 06 
95.70 
93.10 



86. 31 

86. 57 

81. 95 

- 88. 02 

84. 40 



8.5.73 
87.73 



83 

Table 35. — Results obtained in artificial digestion of saynples of different cuts of beef, 
raw and cooked in different ivays — Continued. 



Labo- 
ra- 
tory 
No. 



Description of sample. 



1302 
1303 
1305 



1306 
1.307 
1309 



1314 
1313 



1331 
1.330 



1348 
1.347 



1388 
1389 
1390 

1391 
1392 



1393 
1394 
1395 
1396 
1397 



1399 
1400 
1401 

1402 
1403 



1462 
1463 
1464 
1465 

1520 
1537 

1521 
1536 

1522 
1538 

1535 
1539 

1541 
1540 



Digested 2 Aowrs— Continued. 



Experiments Nos. 29-31 : 
Beef sirloin, very fat, 

Do 

Do 



Average of 3. 



Experiments Nos. 32-34: 

Beef sirloin, very fat, broiled. 

Do ". 

Do 



Average of 3 . 



Experiments Nos. 35-36: 

Beef round, lean, raw 

Beef round, lean, pan broiled, well 

done 

Experiments Nos. 37-38: 

Beef round, lean, raw , 

Beef round, lean, fried in hot lard, 

well done 

Experiments Nos. 39-40: 

Beef round, lean, raw 

Beef round, lean, roasted, well 

done 

Experiments Nos. 41-45: 
Beef round, lean — 

Raw 

Pan broiled 

Cooked in water 2 hours, well 

done , 

Fried in hot lard, well done. . , 

Roasted, well done 

Experiments Nos. 46-50: 
Beef round, lean — 

Raw .■ 

Pan broiled , 

Cooked in water 2 hours 

Fried in hot lard 

Roasted , 

Experiments Nos. 51-55: 

Beef, different cuts, all cooked in 
water 2 hours — 

First cut ribs, very fat , 

Leg bone, moderately fat 

Second cut, neck, moderately 

fat 

Flank, very fat 

Round, rather fat 

Experiments Nos. 66-70: 

Beef, different cuts, all cooked in 
water 2 hours — 

Leg bone 

Second cut, neck 

Flank, well done 

Round, well done 

Experiment No. 81: 

Beef ribs, very fat, raw 

Beef ribs, very fat, roasted 

Experiment No. 82: 

Beef ribs, very fat, raw 

Beef ribs, very fat, roasted 

Experiment No. 83: 

Beef ril)s, very fat, raw 

Beef ribs, verj' fat, roasted , 

Experiment No. 84: 

Beef ribs, very fat, raw 

Beef ribs, very fat, roasted 

Experiment No. 85: 

Beef ribs, very fat, raw 

Beef ribs, very fat . roasted 



Num- 
ber of 
tests 
in av- 
erage. 



Nitrogen in — 



Meat. 



Gram. 

2 0. 0706 

3 ' .0517 
3 I .0645 



.0623 



4 . 0768 
3 .0806 
3 .0936 



.0837 



.0991 
.0919 
.1060 
.1094 
.0888 
.0940 



.0761 
.0895 

.0925 
.0890 
.0863 



.1049 
.0771 
. 1038 
.1124 
.0949 



.0758 
.0790 

.0686 
.0774 
.0812 



.0763 
.0517 
.0617 
.1046 

.0533 
.0629 

.0519 
.0618 

.0352 
.0532 

.0493 
.0605 

.0470 
.0640 



Undi- 
gested 
por- 
tion. 



Gram. 

0.0085 
.0067 
.0078 



Digest- 
ed por- 
tion. 



Gram. 

0. 0621 
.0450 
.0567 



.0077 



.0546 



. 0098 . 0670 
.0111 .0695 
. 0127 . 0809 



.0112 



.0081 
.0119 
.0126 
.0199 
.0093 
. 0097. 



.0085 
.0074 

.0126 
.0110 

.0087 



.0165 
.0123 
.0164 
.0237 
.0078 



.0101 
.0176 

.0140 
.0207 
.0087 



.0112 
.0133 
.0158 
.0130 

.0049 
.0083 

.0072 
.0092 

.0045 
.0084 

.0047 
.0108 

.0075 
.0107 



.0725 



.0910 
.0850 
.0934 
.0895 
.0795 
.0843 



.0676 
.0821 

.0799 
.0780 
.0776 



.0884 
.0648 

.0874 
.0887 
.0871 



.0657 
.0614 

.0546 
.0567 
.0725 



.0651 
.0384 
.0459 
.0916 

.0484 
.0646 

.0447 
.0526 

.0307 
.0448 

.0446 
.0497 

.0395 
.0533 



Proportion of total ni- 
trogen in digested 
• portion. 



Aver- 
age. 



Per ct. 
87.96 
87.04 
87.91 



87.64 



87.24 
86. 23 
86.43 



Mini- 
mum. 



Per ct. 
87.70 
86.06 
86.59 



86. 59 
86.12 
85.99 



Maxi- 
mum. 



Per ct. 
88.21 
88.28 
89.13 



86.63 



91.83 

87.72 
88.11 
81.81 
89. .53 
89.68 



88.83 
91.73 

86.38 
87.64 
89.92 



84.27 
84.05 
84.20 
78.91 
91.78 



86.68 

77.72 

79.59 
73.26 
89.29 



85.32 
74.28 
74.39 
87.57 

90.81 
86.80 

86. 13 
85.11 

87.22 
84.21 

90.47 
82.15 

84.04 
83.28 



9L67 
86.81 
87.62 
80.30 
88.54 
89.08 



88.22 
9L16 

84.17 
86.24 
89.09 



83.85 
83.69 
84.03 



91.67 



85.57 
75.33 

78.51 
72.71 

88.57 



85.18 
69.41 
70.52 
86.84 

87.10 
85.61 

82.53 
84.82 

84.55 
83.15 

89.44 
79.97 

83.19 
82.37 



88.26 
86. 50 
87.16 



91.89 
88.86 
88.77 
82.74 
90.05 
90.60 



89.90 
92. 79 

88.48 
88.87 
90.42 



84.67 
84.74 
84.25 



91.81 



87.40 
80.18 

80.71 
73.71 
90.01 



85.45 
77.72 
78.37 
88.58 

93.71 
87.95 

90.22 
85.51 

89.49 
85.46 

91.53 
84.45 

84.46 
84.53 



84 

Table 35. — Results obtained in artificial digestion of samples of different cuts of beef, 
rail' and cooked in different uays — Continued. 



Labo- 


1 

• 
Description of sample. 


Num- 
ber of 
tests ; 
inav-' 
erage. 


Nitrogen ir 


— 


Proportion of total ni- 
trogen in digested 
portion. 


ra- 
tory 
No. 


Meat. 

i 


Undi- 1 
gested 
por- 
tion. 


Digest-' 
ed por- 
tion. 


Aver- 
age. 


Mini- 
mum. 


Maxi- 
mum. 


1587 

1588 ; 


Digested 2 ftours— Continued. 

Experiment No. 91: 

Beef ribs, very fat, roasted 

Do 

Average of 2 '. . 

Experiment No. 92: 

Beef ribs, verv fat, roasted 

Do ". 


4 

2 


Gram. 

0.0638 

.0614 


Gram, j 

0.0099 

.0125 


Gram. 

0.0539 

.0489 


Per ct. 
84.48 
79.64 


Per ct. 
83.51 
79.41 


Per ct. 
84.95 
79.93 






.0626 j 


.0112 


.0514 


82.06 












1589 
1590 


2 
3 


1 
. 0736 1 
.0536 ; 


.0150 
.0095 


-.0586 
.0441 


79.62 
82.27 


79.52 
81.53 


79.77 
83.37 




Average of 2 

Experiment No. 93: 

Beef ribs, very fat, roasted 

Do 

Average of 2 

Average of 6 

Experiment No. 94: 

Beef ribs verv fat. raw. 








.0636 


.0123 


.0513 


80.95 












1591 
1595 


2 
4 


.0731 
.0553 


.0195 
.0092 


.0536 
.0461 


73.32 
83.36 


73.09 
81.22 


73.64 
85.09 






.0642 i 


.0144 


.0498 


78.34 
















.0635 


.0126 


.0509 


80.45 












1611 


4 

4 

3 
3 

2 
4 


.0654 
.0613 

.0599 
.0527 

.0781 
.0588 


*■ .0118 
.0141 

.0084 
.0099 

.0126 
.0083 


.0536 
.0472 

.0515 
.0428 

.0655 
.0505 


81.96 
77.00 

85.98 
81.21 

83.87 
85.88 


79.60 
76.21 

85.00 
80.08 

81.95 
82.54 


85.92 


1615 
1612 


Beef ribs, very fat, roasted 

Experiment No. 95: 

Beef ribs, verv fat, raw 


77.87 
87.66 


1614 
1613 


Beef ribs, very fat, roasted 

Experiment No. 96: 

Beef ribs, verv fat, raw. 


82.39 
85.43 


1616 


Beef ribs, very fat, roasted 

Experiment No. 97: 

Beef ribs, very fat, roasted 

Do 


88.00 


1525 
1561 


3 
3 

3 


.0689 
.0809 
.0625 


.0120 
.0174 
.0073 


.0569 
.0635 
.0552 


82.58 
78.49 
88.32 


81.86 
78.40 
88.07 


82.86 
78.72 


1617 


Do 

Average of 3 

Experiment No. 94: 

Beef round, cooked in water 2 
hours, ground twice in a sausage 
mill 


88.58 




. 0708 


.0122 


.0585 


83.13 












1634 


4 
3 

4 
3 
4 
5 
4 

4 
4. 
4 
4 
4 

3 
3 
4 
4 
3 

2 


.1431 
.1100 

.0923 
.0612 
.0595 
.0653 
.0763 

.0916 
.0830 
.1118 
.0689 
.0907 

.0922 
.0495 
.0902 
.0931 
.0936 

i .0392 


. 0257 
.0831 

.0053 
.0055 
.0047 
.0095 
.0101 

.0056 
.0046 
.0055 
.0047 
.0102 

.0089 
.0018 
.0047 
.0050 
.0058 

.0025 


.1174 
.0269 

.0870 
.0557 
.0548 
.O-VW 
.0662 

.0860 
.0784 
.1063 
.0642 
.0805 

.0833 
.0477 
.0855 
.0881 
.0878 

' .0367 


82.04 
24.45 

94.26 
91.01 
92.10 
85.45 
86.76 

93.89 
94.46 
95.08 
93. 18 
, 88.75 

i 

' 90.35 
96.36 

. 94.79 
94.63 
93.80 

93.62 


80.69 
23.34 

93.96 
90.99 
91.35 
84.25 
84.80 

93.25 
92.74 
94.93 
92.50 
88.21 

89.50 
96.33 
94.28 
94.14 
93.56 

93.12 


83.96 


1635 
1202 


Experiment No. 95: 

Beef round, cooked in water 2 
hours, cut into quarter-inch 
cubes 

Digested 4 hours. 

Experiments Nos. 7-11: 
Beef round- 
Raw 


26.20 
94.40 


1203 


Pan broiled 


91.06 


1204 


Fried in hot lard 


92.79 


1205 
1206 

1210 


Cooked in water 2 hours 

Cooked in water 5 hours 

Experiments Nos. 12-16: 
Beef round, lean- 
Raw 


1 87. 12 
89.39 

1 

94.36 


1211 
1212 
1215 


Cooked in water 2 hours 

Cooked in water 5 hours 

Pan broiled 


95.38 

i 95. 19 

94.05 


1219 


Fried in hot lard 


89.25 


1235 


Experiments Nos. 17-21: 
Beef round. lean- 
Raw 


91.43 


1238 


Pan broiled 


96.43 


1241 


Fried in hot lard 


95. 72 


1242 
1243 

1279 


Cooked in water 1 hour 

Cooked in water 5 hours 

1 Experiments Nos. 22-26: 

Beef sirloin, very fat, broiled, 
1 underdone 


95.28 
. 93.97 

' 94. 36 



85 

Table 35. — Results ohtained in artificial digestion of samples of different cuts of beef,' 
raw and cooked in different ways — Continued. 



Labo- 
ra- 
tory 
No. 



1280 

1281 

1282 
1283 



1287 

1300 

1302 
1303 
1305 



1306 
1307 
1309 



1314 
1313 



1331 
1330 



1348 
1347 



1388 
1389 
1390 

1391 
1392 



1393 
1394 
1395 
1396 
1397 



1399 
1400 
1401 

1402 
1403 



1462 
1463 
1464 
1465 



Description of sample. 



Digested 4 hours — Continued. 

Beef sirloin, very fat, broiled, well 
done , 

Beef sirloin, very fat, broiled, under- 
done 

Do 

Do :..., 



Average of 5. 



Experiments Nos. 27-28: 

Beef shoulder, very fat, cooked in 

water 2 hours 

Beef shoulder moderately fat, raw. 
Experiments Nos. 29-31: 

Beef sirloin, verv fat, raw 

Do .' 

Do 



Average of 3. 



Experiments Nos. 32-34: 

Beef sirloin, very fat, broiled. 

Do 

Do 



Average of 3. 



Experiments Nos. 35-36: 

Beef round, lean, raw 

Beef round, lean, pan broiled, well 

done 

Experiments Nos. 37-38: 

Beef round, lean, raw 

Beef round, lean, fried in hot lard, 

well done 

Experiments Nos. 39-40: 

Beef round, lean, raw 

Beef round, lean, roasted, well 

done 

Experiments Nos. 41-45: 
Beef round, lean — 

Raw 

Pan broiled 

Cooked in water 2 hours, well 

done 

Fried in hot lard, well done 

Roasted, well done 

Experiments Nos. 46-50: 
Beef round, lean — 

Raw 

Pan broiled 

Cooked in water 2 hours 

Fried in hot lard 

Roasted 

Experiments Nos. 51-55: 

Beef, different cuts, all cooked in 
water 2 hours — 

First cut ribs, very fat 

Leg bone, moderately fat 

Second cut, neck, moderately 

fat 

Flank, very fat 

Round, rather fat 

Experiments Nos. 67-70: 

Beef,|different cuts, all cooked in 
warer 2 hours — 

Leg bone 

Second cut, neck 

Flank, well done 

Round, well done 



Num- 
ber of 
tests 
in av- 
erage. 



Nitrogen in- 



Meat. 



Gram. 
0.0688 

.0537 
.0555 
.0843 



.0603 



. 0965 
. 1146 

.0710 
.0574 
.0602 



.0629 



.0907 
.0809 
.0965 



.0894 



.0884 
.0928 
.0932 
.1168 
.1034 
.1066 



.0909 
.0863 

.1035 
.0913 
.0940 



.0847 
.0733 
.0990 
.1045 
.0875 



.0823 
.0946 

. 0751 
.0721 
.0953 



.0765 
.0481 
.0580 
.1038 



Undi- 
gested 
por- 
tion. 



Gram. 
0.0063 

.0093 
.0038 
.0074 



.0059 



.0085 
.0106 

.0051 
.0041 
.0032 



.0041 



.0091 

.0068 
.0089 



.0083 



.0051 
.0084 
.0054 
.0115 
.0070 
.0062 



.0056 
.0044 

.0105 
.0079 
.0105 



.0091 
.0073 
.0123 
.0150 
.0067 



.0092 
.0137 

.0091 
.0107 
.0072 



.0068 
.0069 
.0106 
.0075 



Digest- 
ed por- 
tion. 



Gram. 
0. 0625 

.0444 
.0517 
.0769 



.0544 



.0880 
.1040 

.0659 
.0533 
.0570 



.0587 



.0816 
.0741 
.0876 



.0811 



.0833 
.0844 
.0878 
.1053 
.0964 
.1004 



.0853 
.0819 

.0930 
.0834 
.0835 



.0756 
.0660 
.0867 
.0895 
.0808 



.0731 
.0809 

.0660 
.0614 
.0881 



.0697 
.0412 
.0474 
.0963 



Proportion of total ni- 
trogen in digested 
portion. 



Aver- 
age. 



Per ct. 
90.84 

82.68 
93.15 
91.22 



90.30 



91.19 
90.75 

92.82 
92.86 
94.68 



93.45 



89.97 
91.59 
90.78 



90.78 



94.23 
90.95 
94.21 
90.15 
93.23 
94.19 



93.84 
94.90 

89.86 
91.35 
88.83 



89.26 
90.04 

87.58 
85.65 
92.34 



88.82 
85.52 

87.88 
85.16 
92. 44 



91.11 

85.65 
81.72 
92.77 



Mini- 
mum. 



Per ct. 
89.99 



92.73 
90.93 



90.87 
90.35 

92.43 
92.33 
94.40 



89.26 
90.96 
90.10 



94. 03 
90.10 
92.35 
89.27 
92.92 
93. 69 



93.05 
94.27 

89.76 
90.82 
88.11 



89.09 
89.15 
86.22 
84.41 
90.44 



87.43 
84.35 

87.08 
82.86 
90.19 



90.33 
83.29 
80.54 
91.86 



Ma.xi- 
mum. 



Per ct. 
91.74 



93.29 
91.58 



91.88 
91.21 

93.61 
93.42 
94.97 



91.03 
92.32 
91.40 



94.44 
91.40 
95.61 
90.84 
93.60 
94.56 



94.18 
95.73 

90.81 
91.63 
90.64 



89.40 
90.90 
89.57 
86.51 
93.80 



89.67 
87.56 

88.75 
87.87 
94.74 



91.82 

88.57 
82.88 
93.52 



86 

Table 35.- — ncsiills ohlained in arlijicial digestion of samples of (Uffrrent evts of lieef 
raw and eooked in differenl vays — Continued. 



Labo- 


Description of sample 


Num- 
ber of 
tests 
in av- 
erage. 


Nil 
Meat. 

Gram. 

0. 0816 
.0717 
.0648 
. 0634 
. 0709 

.0843 
.0939 
.1010 
.0719 
.0869 

. 095() 
.0719 
. 0935 
.0931 
. 0923 

.0659 

.0708 

.0418 
.0475 
.0787 

.0910 
.1153 

.0757 
.0662 
.0676 


.rogen in 


— 


Proportion of total ni- 
trogen in digested 
portion. 


tory 
No. 


Undi- 
gested 
por- 
tion. 


Digest- 
ed por- 
tion. 


. Aver- 
age. 


Mini- 
mum. 


Maxi- 
mum. 


1202 


Digested G /lours. 

Experiments Nos. 7-11: 
T5eef round- 
Raw 


4 
4 
4 
4 

3 

4 
3 
4 
3 
3 

3 
3 
4 
4 
4 

2 

3 

3 
3 
3 

3 
4 

3 
4 
3 


Gram. 

0. 0039 
.0033 
. 0032 
.0071 
. 00.50 

.0041 
.0031 
.0065 
.0037 
.0084 

.0048 
.0022 
.0038 
.0041 
.0033 

.0041 

.0046 

.0040 
. 0026 
.0053 

.0081 
.0074 

.0038 
.0039 
.0011 


Gram. 

0. 0777 
.0684 
.0616 
.0563 
. 0('i.59 

.0802 
.0908 
.0945 
.0682 
.0785 

.0908 
.0697 
.0897 
.0890 
.0890 

.0618 

.0662 

. 0378 
.0449 
. 07.34 

.0829 
.1079 

.0719 
.0623 
.0665 


Per ct. 
95.22 
95.40 
96.06 
88.80 
92.95 

95.14 
96.70 
93.56 
94.85 
90. 33 

94.98 
96.94 
95.94 
95.60 
96.42 

93.78 

93.50 

90.43 
94.53 
93.27 

91.10 
93.59 

94.98 
94.11 
98.37 


Per ct. 
94.17 
94.76 
94.21 
87.48 
92.09 

94.65 
96.08 
91.22 
94.47 
89.46 

94.18 
96. 65 
95.67 
95.49 
96.04 

93.67 

92.78 

89.76 
94.03 
93.18 

89.82 
93.53 

94.13 
93.13 
98.26 


Per ct. 
95.68 


1203 


Pan liroiled 


96.36 


1204 


Fried in hot lard 


95. 76 


1205 
1206 

1210 


Cooked in water 2 hours 

Cooked i ii water 5 hours 

Experiments Nos. 12-16: 
Beef, round, lean- 
Raw 


89.63 
93.44 

95. 30 


1211 
1212 
1215 


Cooked in water 2 hours 

Cooked in water 5 hours 

Pan broiled . 


96.96 
95.17 
95.11 


1219 


Fried in hot lard 


91.08 


1235 


Experiments Nos. 17-21: 
Beef, round, lean — 

Raw 


95.71 


1238 


Pan 1) roiled 


97.22 


1241 


Fried in hot lard 


96.13 


1242 
1243 

1279 


Cooked in water 1 hour 

Cooked in water 5 hours 

Experiments Nos. 22-26: 

Beef sirloin, very fat, broiled, un- 
derdone 


95.72 
97.36 

93.74 


1280 


Beef sirloin, very fat, broiled, well 
done 


93.96 


1281 


Beef sirloin, very fat, broiled, un- 
derdone .- 


90.97 


1282 


Do. 


95.06 


1283 


Do 


93.35 


1287 


Experiments Nos. 27-28: 

Beef shoulder, very fat, cooked in 
water 2 hours 


92.31 


1300 

1302 
1303 


Beef shoulder, moderately fat, raw 
Experiments Nos. 29-31 : 

Beef sirloin, verv fat, raw 

Do ' 


93.73 

96.05 
95.29 


1305 


Do. . . . 


98.63 




Averaee of 3 








.0698 


.0029 


.0669 


95.82 








Experiments Nos. 32-.34 : 

Beef sirloin, very fat, broiled 

Do ■. 






1306 
1307 


3 
4 
4 


. 0760 
.0772 
.0948 


.0055 
.0051 
.0062 


.0705 
.0721 
.0886 


92.76 
93.39 
93.46 


92.61 
93.14 
92.52 


92.93 
93.60 


1309 


Do 


94.79 




Average of 3 








.0827 


.0056 


.0771 


93.20 








Experiments Nos. 35-36: 

Beef round, lean, raw 








1314 


4 
3 
3 
3 
4 
4 

4 
3 

3 
3 
4 

4 
3 
4 
3 
3 


.1045 
.1127 
.0933 
.1001 
.0904 
.1015 

. 0966 
.1067 

.0892 
.0927 
.0099 

.0951 
.0704 
.0955 
.0945 
.1093 


.0053 
.0081 
.0051 
.0085 
.0046 
.0054 

. 0037 
.0047 

.0042 
.0002 
.0055 

.0078 
.0042 
. 0052 
.0110 
.0077 


.0992 
.1046 
.0882 
.0916 
.0858 
.0961 

.0929 
.1020 

.0850 
.0865 
.0940 

.0873 
. 0662 
.0903 
.0835 
.1016 


94. 93 
92.81 
94.53 
91.51 
94.91 
94.68 

96.17 
95.60 

95.2^ 
93.31 

94.47 

91.80 
94.03 
94.55 
88.36 
92.95 


94.41 
92.44 
94.47 
91.20 
94.06 
94.22 

95. 67 
94. 96 

94.88 
93.18 
94.01 

91.61 
91.49 
y3. 93 
86. 17 
92.34 


95.39 


1313 


Beef round, lean, pan broiled, well 
done 


93. 20 


1331 


Experiments Nos. 37-38: 

Beef round, loan, raw 


94. 68 


1330 


Beet round, lean, fried in hot lard, 
well done 


91.89 


1348 


Experiments Nos. 39-40: 
Beef round, lean, raw. 


95.46 


1347 


Beef round, lean, roasted, well 
done - . . 


94.96 


1388 


Experiments Nos. 41-45: 
Beef round, lean — 

Raw 


96. 53 


1389 


Pan broiled . . . . 


96.59 


1390 


Cooked in water 2 hours, well 
done 


95. 62 


1391 
1392 


Fried in hot lard, well done 

Roasted , well done 


93.38 
95. 32 


1393 


Experiments Nos. 46-50: 
Beef round, lean—. 

Raw 


91. 80 


1394 


Pan broiled 


95.90 


1395 
1396 


Cooked in water 2 hours 

Fried in hot lard 


95. 28 
89. 69 


1397 


Roasted 


94.00 



87 

Table 35. — Results obtained in artificial digestion of sainples of different cuts of beef,' 
raw and cooked in different ways — Continued. 



Labo- 


Description of sample. 


Num- 
ber of 
tests 
in av- 
erage. 


Ni 


trogen in — 


Proportion of total ni- 
trogen in digested 
portion. 


ra- 
tory 
No. 


Meat. 


Undi- 
gested 
por- 
tion. 


Digest- 
ed por- 
tion. 


Aver- 
age. 


Mini- 
mum. 


Maxi- 
mum. 


1399 
1400 
1401 

1402 
1403 

1461 
1462 


Digested 6 hours— Conthmed. 

Experiments Nos. 51-55: 

Beef, different cuts, all cooked in 
water 2 hours — 

First cut ribs, very fat 

Leg bone, moderately fat 

Second cut, neck, moderately 

fat 

Flank, very fat 

Round, rather fat 

Experiments Nos. 66-70: 

Beef, different cuts, all cooked in 
water 2 hours- 
First cut ribs, underdone 

Leg bone 


3 
4 

3 
3 
2 

3 
2 

3 
4 
4 

3 
2 

4 
4 

4 
4 
3 

4 
3 
2 
3 
4 

4 

2 
4 
4 
3 

4 
3 


Gram. 

0. 0695 

.0855 

.0660 
.0741 
.0801 

.0547 
.0830 
.0522 
.0535 
.0958 

.1303 

.1439 

.0833 
.0739 
.0679 
.0680 
.0722 

• 

.0821 
.0886 
.1189 
.0836 
.0905 

.0828 
.0613 
.0902 
.0954 
.0730 

.1006 
.0989 


Gram. 

0.0059 

.0084 

.0054 
.0095 
.0058 

. 00.57 
.0061 
.00.57 
.0076 
.0046 

.0077 

.0872 

.0025 
. 0026 
.0025 
.0031 
.0026 

.0026 
.0029 
.0056 
.0038 
.0051 

.0030 
.0020 
.0020 
.0027 
.0022 

.0034 
.0027 


Gram. 

0. 0636 

0771 

.0606 
. 0646 
.0743 

.0490 
.0769 
.0465 
.0459 
.0912 

.1226 

.0567 

.0808 
.0713 
. 0654 
.0649 
.0696 

.0795 
.0857 
.1133 
.0798 
.0854 

.0798 
.0593 
. 0882 
.0927 
.0708 

.0972 
.0962 


Per ct. 
91.51 
90.18 

91.82 
87.18 
92.76 

89.58 
92.65 
89.08 
85.79 
95. 20 

94.09 

39. 40 

97.00 
96.48 
96.32 
95.44 
96.40 

96.83 
96. 73 
95.29 
95 45 
94.36 

96.38 
96.74 
97.78 
97.17 
96.99 

96.62 
97.27 


Per ct. 
90.31 

89.24 

90.43 
86.76 
91.98 

88.28 
92. 63 
88.59 
84.38 
94.61 

93.89 

3.5. 17 

96.53 
96.02 
96.03 
95.09 
95.93 

96.41 
96. 56 
94.94 
95.34 
94.14 

95.71 
96.51 
97.38 
97. 03 
96.73 

95.99 
97.04 


Per ct. 
92.36 
91.33 

93.76 
89.55 
93.50 

90.69 
92.67 


1463 


Second cut neck 


89.74 


1464 


Flank, well done 


86.90 


1465 


Round, well done 


95.92 


1634 


Experiment No. 94: 

Beef round, cooked in water 2 
hours, ground twice in a sausage 
mill 


94.63 


1635 


Experiment No. 9.'i: 

Beef round, cooked in water 2 
hours, cut into quarter-inch 
cubes 


42.03 


1202 


Digested S4 hours. 

Experiments Nos. 7-11: 
Beef round- 
Raw . . 


97.74 


1203 


Pan broiled 


97.04 


1204 


Fried in hot lard 


96.54 


1205 
1206 

1210 


Cooked in water 2 hours 

Cooked in water 5 hours 

Experiments Nos. 12-16: 
Beef round, lean- 
Raw 


95.64 
96.63 

97.20 


1211 
1212 
1215 


Cooked in water 2 hours 

Cooked in water 5 hours 

Pan broiled 


96.90 
95.53 
95.41 


1219 


Fried in hot lard 


94.64 


1235 


Experiments Nos. 17-21: 
Beef round, lean- 
Raw 


96.95 


1238 


Pan broiled 


97.04 


1241 


Fried in hot lard 


98.40 


1242 
1243 

1287 


Cooked in water 1 hour 

Cooked in water 5 hour's 

Experiments Nos. 27-28: 

Beef shoulder, very fat, cooked in 
water 2 hours. . . . 


97.28 
97.21 

97.37 


1300 


Beef shoulder, moderately fat, raw. 

Experiments Nos. 29-31: 

Beef sirloin, very fat, raw 


97.61 


1302 


2 
3 
2 


.0775 
.0557 
.0732 


.0007 
.0007 
.0036 


.0768 
.0550 
.0696 


99.10 
98.74 
95.08 


98. 36 
97.80 
95.00 


100.00 


1303 


Do 


99.09 


1305 


Do 


95.16 




Average of 3 








.0688 


.0017 


.0671 


97.64 








Experiments Nos. 32-34: 

Beef sirloin, very fat, broiled 

Do 








1306 
1307 


3 
2 
2 


.0910 
.0701 
.0976 


.0037 
.0025 
.0022 


.0873 
.0676 
.0954 


95.93 
96.51 
97.75 


95.63 
96.43 
96.64 


96.07 
96.59 


1309 


Do 


98.52 




Average of 3 








.0862 


.0028 


.0834 


96.73 








Experiments Nos. 35-36: 

Beef round, lean, raw 








1314 


4 
4 


.1158 
.0979 


.0032 
.0034 


.1126 
.0945 


97.24 
96.53 


96.94 
96.20 


97.44 


1313 


Beef round, lean, pan broiled, well 
done 


96.75 



88 

Table 35. — Results obtained inartificial digestion of samples of different cuts of beef, 
raw and cooked in different ways — Continued. 



Labo- 


Description of sample. 


Num- 
ber of 
tests 
in av- 
erage. 


Nitrogen in— 


Proportion of total ni- 
trogen in digested 
portion. 


tory 
No. 


Meat. 


Undi- 
gested 
por- 
tion. 


Digest- 
ed por- 
tion. 


Aver- 
age. 


Mini- 
mum. 


Maxi- 
mum. 


1331 
1330 


Digested M hours — Continued. 

Experiments Nos. 37-38: 

Beef round, lean, raw 

Beef round, fried in hot lard, well 
done 


3 

4 


Gram. 
0.0977 

.12:<9 


Gram. 
0.0025 

.0044 

.0038 

.0057 

.0019 
.0014 

.0044 
.0022 
.0022 

.0034 
.0022 
.0023 
■•■ . 0037 
.0024 


Gram. 
0.0952 

.1195 

.0892 

,1145 

.0832 
.0768 

.1004 
.0782 
.0808 

.0954 
.0742 
.0725 
.0991 
.0917 


Per ct. 
97.44 

96.45 

9.i. 91 

95.34 

97.77 
98.21 

95. 80 
97.26 
97.35 

96.56 
97.12 
96.93 
96.40 
97.45 


Perct. 
97.40 

96.23 

95.59 

94.87 

97.66 
97.89 

95. 05- 
96.76 
96.65 

96.49 
96.67 
96.83 
96.00 
97.26 


Per ct. 
97.50 

96 70 


1348 


Experiments Nos. 39-40: 

Beef round, lean, raw 


4 -09.'?n 


96 17 


1347 


Beef round, lean, roasted, well 
done ■. 


3 

4 
3 

3 
4 
3 

4 
3 

4 

4 
4 


.1202 

.0851 
.0782 

.1048 
.0804 
.0830 

.0988 
.0764 
.0748 
.1028 
.0941 


95 84 


1388 


Experiments Nos. 41-45: 
Beef round, lean- 
Raw 


97 92 


1389 


Pan broiled 


98.46 


1390 


Cooked in water 2 hours, well 
done 


96 80 


1391 
1392 


Fried in hot lard, well done . . . 
Roasted, well done. 


97. 62 
97 G6 


1393 


Experiments Nos. 46-50: 
Beef round, lean- 
Raw 


96 62 


1394 


Pan broiled 


97.92 


1395 
1396 


Cooked in water 2 hours 

Fried in hot lard 


97.20 
96 89 


1397 


Roasted 


97 55 




Experiment No. 92: 

Beef ribs, very fat, roasted 

Do 




1589 
1590 


2 
3 


.0761 
.0580 


.0059 
.0028 


.0702 
.0552 


92.25 
95.11 


91.54 
95.06 


92.85 
95.16 




Average of 2 








.0671 


.0044 


.0627 


93.68 








Experiment No. 93: 

Beef ribs, very fat, roasted 

Do 








1591 
1595 


3 
3 


.0711 
.0581 


.0047 
.0033 


.0664 
.0548 


93.39 
94.32 


92.78 
93.78 


94.31 
95 14 




Average of 2 








.0646 


.0040 


.0606 


93.86 








Average of 6 '. 












.0683 


.0040 


.0643 


94.21 








Experiment No. 94: 

Beef ribs, very fat, raw 








1611 


3 
3 

2 
3 

3 
3 


.0662 
.0488 

.0679 
.0523 

.0756 
.0596 


.0056 
.0027 

.0025 
.0033 

.0040 
.0029 


.0606 
.0461 

.0654 
.0490 

.0716 
.0567 


91.54 
94.47 

96. 32 
93. 69 

94.71 
95.13 


91.31 
94.09 

95.44 
92.87 

94.41 
95.00 


91.67 


1615 
1612 


Beef ribs, very fat, roasted 

Experiment No. 95: 

Beef ribs, very fat, raw 


94.71 
97.01 


1614 
1613 


Beef ribs, very fat, roasted 

Experiment No. 96: 

Beef ribs, very fat, raw 


94.47 
95.02 


1616 


Beef ribs, very fat, roasted 

Experiment No. 97: 

Beef ribs, very fat, roasted 

Do 


95.41 


1525 
1561 


3 
3 
3 


.0582 
.0800 
.0523 


.0028 
.0036 
.0028 


.0554 
.0764 
.0495 


95.19 
95.50 
94.65 


94.75 
94.60 
94.26 


95.87 
96.03 


1617 


Do. 


94 71 




Average of 3 








.0635 


.0031 


.0604 


95.11 








Experiment No. 94: 

Beef round, cooked in water 2 
hours, ground twice in a sausage 
mill 








1634 


4 

3 

2 
3 

3 
2 
3 


.1088 

.0996 

.0796 
.0745 

.0898 
.0590 
.0848 


.0034 

.0108 

.0032 
.0026 

.0064 
.0042 
.0056 


.1054 

.0888 

.0764 
.0719 

.0834 
.0548 
.0792 


96.87 

89. 16 

95.98 
96.51 

92.87 
92.88 
93.40 


96. 43 

86.81 

95.12 
95.94 

91.92 
90.96 
92.68 


97.18 


1635 


Experiment No. 95: 

Beef round, cooked in water 2 
hours, cut into quarter-inch 
cubes 


91.97 


1399 
1400 
1401 


Experiments Nos. 51-55: 

Beef, different cuts, all cooked in 
water 2 hours — 

First cut ribs, very fat 

Leg bone, moderately fat 

Second cut neck, moderately 
fat 


96.73 
96.94 

94.03 


1402 


Flank, very fat 


94.71 


1403 


Round, rather fat 


93.73 



89 



Table 35. — Results obtained in artificial digestion of samples of different cuts of beef, 
raw and cooked in different ways — Continued. 



Labo- 


Description of sample. 


Num- 
ber of 
tests 
in av- 
erage. 


Nitrogen in— 


Proportion of total ni- 
trogen in digested 
portion. 


ra- 
tory 
No. 


Meat. 


Undi- 
gested 
por- 
tion. 


Digest- 
ed por- 
tion. 


Aver- 
age. 


Mini- 
mum. 


Maxi- 
mum. 


1461 
1462 


Digested 34 feoMrs— Continued. 

Experiments Nos. 66-70: 

Beef, different cuts, all cooked in 
water 2 hours- 
First cut ribs, underdone 

Leg bone 


2 
4 


Oram. 

0. 0607 

.0841 


Gram. 

0. 0032 
.0029 
.0027 
.0026 
.0032 

.0027 
.0020 

.0024 
.0036 

.0018 
.0030 

.0017 
.0027 

.0024 
.0029 


Gram. 

0. 0575 
.0812 
.0560 
.0572 
.0974 

.0505 
.0575 

.0443 
.0536 

.0317 
.0530 

.0537 
.0489 

.0500 
.0632 


Per ct. 
94.73 
96.55 
95.40 
95.65 
96.82 

94.92 
95.67 

94.86 
93.71 

94.63 
94.64 

96.93 
94.77 

95.42 
95.51 


Per ct. 
94.43 
96.51 


Per ct. 
94.97 
96.78 


1463 


Second cut neck 


3 . 0587 


95.11 ; 9.5.75 


1464 


Flank, well done 


3 
4 

1 
4 

2 
3 

3 
3 

3 
2 

3 
2 


.0598 
.1006 

.0.532 
.0601 

.0467 
.0572 

.0335 
.0560 

.0554 
.0516 

.0524 
.0661 


95.29 
96.10 


96.14 


1465 


Round, well done. 


97.12 


1520 


Experiment No. 81: 

Beef ribs, very fat, raw 




.1537 
1521 


Beef ribs, very fat, roasted 

Experiment No. 82: 

Beef ribs, very fat, raw. 


94.75 

94.46 
92.75 

93.03 
94.25 

96.40 
94.61 

95.09 
95.32 


96.90 
95.09 


1536 
1522 


Beef ribs, very fat, roasted 

Experiment No. 83: 

Beef ribs, very fat, raw 


94.85 
96.29 


1538 
1535 


Beef ribs, very fat, roasted 

Experiment No. 84: 

Beef ribs, very fat, raw. 


95.35 
97.45 


1539 

1541 
1540 


Beef ribs, very fat, roasted 

Experiment No. 85: 

Beef ribs, very fat, raw 

Beef ribs, very fat, roasted 

Experiment No. 91: 

Beef ribs, very fat, roasted 

Do 


94.73 

95.80 
95.70 


1587 
1588 


4 
1 


.0666 
.0797 


.0033 
.0039 


.0633 
.0758 


95.05 
95.11 


94.31 


95.27 




Average of 2 » . . 










.0732 


.0036 


.0696 


95.08 

















EXPERIMENTS WITH MUTTON. 

The work with mutton consisted of a study of the relative ease of 
digestion of different cuts from the same animal, which was a wether 
about 2 years old when slaughtered. Five different cuts were used. 
No. 1424 was a shoulder, very fat; No. 1425 was a flank piece, very 
fat; No. 1426 was a leg, moderately fat; No. 1427 was a piece of 
loin, very fat; and-No. 1428 was a rib piece, very fat. Each of these 
was cooked in water that was kept boiling for ten minutes, and then 
at 80°-85° for two hours. The experiments with these pieces of meat, 
Nos. 56 to 60, are given in Table 36. 



90 

Table 3G. — Results obtained in artificial digestion of different cuts of mutton, all cooked 

in the same manner. 



Lab- 
ora- 
tory 
No. 



1424 
1425 
1426 
1427 
1428 



1424 
1425 
1426 
1427 
1428 



1424 
1425 
1426 
1427 
1428 



1424 

1425 
1426 
1427 
1428 



1424 
1425 
1426 
1427 
1428 



Description of sample. 



Digested 1 hour. 

Experiments Nos. 56-60: 

Mutton, different cuts, all cooked 
in water 2 hours- 
Shoulder 

Flank 

Leg 

Loin 

Ribs 

Digested i tiours. 

Experiments Nos. 56-60: 

Mutton, different cuts, all cooked 
in water 2 hours- 
Shoulder 

Flank 

Leg 

Loin 

Ribs 

Digested 4 hours. 

Experiments Nos. .')6-60: 
Mutton — 

Shoulder 

Flank 

Leg 

Loin ■. .. 

Ribs 

Digested 6 hours. 

Experiments Nos. 56-60: 
Mutton — 

Shoulder 

Flank 

Leg 

Loin 

Ribs 

Digested 34 hours. 

Experiments Nos. 56-60: 
Mutton — 

Shoulder 

Flank 

Leg 

Loin 

Ribs..... 



Num- 
ber of 
tests 
in av- 
erage. 



Nitrogen- 



Proportion of total ni- 
trogen in digested 
portion. 





In 


In 


undi- 


meat. 


gested 




residue. 


Gram. 


Gram. 


0. 0760 


0.0135 


.0647 


.0193 


.0686 


.0100 


. 0577 


.0140 


. 0557 


.0111 


.0765 


.0118 


.0715 


.0126 


. 0618 


. 0070 


. 0555 


.0095 


.0552 


.0091 




\ 


.0699 


.0087 


.0571 


.0091 


.0669 


.0046 


. 0552 


.0062 


.0668 


.0063' 


.0721 


.0049 


.0694 


.0087 


.0687 


.0035 


.0436 


.0042 


.0615 


.0055 


.0801 


.0037 


.0618 


.0037 


.0720 


.0014 


. 0548 


.0020 


.0672 


.0029 



In di- I 

gested , Aver- 
por- age. 
tion. 



Gram. 

0. 0625 
.0454 
.0586 
.0437 
.0446 



.0647 
.0589 
. 0548 
.0460 
.0461 



.0612 
.0480 
.0623 
.0490 
.0605 



.0672 
.0607 
.0652 
.0394 
.0560 



.0764 
.0581 
.0706 
.0528 
.0643 



Per ct. 
82.24 
70.17 
8.5.42 
75. 74 
80.07 



84.58 
82.38 
88.67 
82.88 
83.51 



87.55 
84.06 
93.12 
88.77 
90.57 



93.20 
87.46 
94.91 
90.37 
91.06 



95.38 
94.01 
98.06 
96.35 
95.68 



Mini- 
mum. 



Per ct. 



68.01 
84.24 
74.30 
79.74 



84.25 
80.75 
88.07 
81.01 
82.64 



82.15 
92.62 
88.01 
87.24 



92.87 
87,19 
93.26 
88.79 
89.06 



95.18 
93.52 
97.27 
96.01 
94.54 



Maxi- 
mum. 



Per ct. 



71.39 
87. 05 
76.83 
80.18 



84.85 
83.26 
89.36 
84.05 
84.27 



85.08 
93.99 
89.35 
92.60 



93.73 

87.95 
96.76 
93.13 
93.20 



95.59 
94.27 
98.94 
96.63 
96.70 



EXPERIMENTS WITH PORK. 

The work with pork inchided experiments with different cuts from 
the same animal, all cooked in the same way, and also tests with the 
same cut from different animals, both raw and roasted. The samples 
used are here described. 

Experiments Nos. Gl to 65 were made with different cuts of pork from a very fat 

animal about 9 months old when slaughtered. No. 1430 was a belly cut, known locally 

.as a flitch piece; No. 1432 was fresh ham; No. 1433 was fresh shoulder, and No. 

1434 was a back cut. Each piece of meat was cooked in water, which was kept boiling 

for ten minutes and then at 80° to 85° for two hours. 

Experiment No. 71 was made with fresh ham from a corn-fed hog 8 months old. 
One piece (No. 1482) was not cooked and one piece (No. 1483) was roasted. 



91 

Experiment No. 72 was made with fresh ham from a corn-fed hog about 8 months 
old. One piece (No. 1485) was not cooked and the other piece (No. 1484) was roasted. 

Experiment No. 73 was made with fresh ham from a corn-fed hog about 8 months 
old. One piece (No. 1487) was not cooked and the other piece (No. 1486) was roasted. 

Experiment No. 74 was made with a fresh ham from an animal about 8 months old 
that had been fed on hominy and gluten meal. One piece (1488) was uncooked and 
the other piece (1489) was roasted. 

Experiment No. 75 was made with fresh ham from a Duroc-Jersey hog about 8 months 
old that had been fed on hominy and gluten meal. One piece (1490) was not cooked 
and the other piece (1491) was roasted. 

Experiment No. 76 was made with fresh ham from a Duroc-Jersey hog al^out 8 
months old that had been fed on hominy and gluten meal. One piece (1492) was 
not cooked and the other piece (1493) was roasted. 

Experiment No. 77 was made with fresh ham from a Duroc-Jersey hog about 9 
months old, fed on corn and clover.' One piece (1505) was not cooked and the other 
piece (1504) was roasted. 

Experiment No. 78 was made with fresh ham from a Duroc-Jersey hog about 8^ 
months old, fed on corn and clover. One piece (1507) was uncooked and the other 
piece (1506) was roasted. 

Experiment No. 79 was made with fresh ham from a Duroc-Jersey hog fed on corn 
and clover. One piece (1510) was uncooked and the other piece (1511) was roasted. 

Experiment No. 80 was made with fresh ham fi'om a Yorkshire hog. One piece 
(1515) was not cooked and the other piece (1514) was roasted. 

Experiment No. 86 was made with fresh ham from a Duroc-Jersey hog about 8 
months old, fed on peas, oats, and l^arley. One portion (1542) was vmcooked and the 
other portion (1545) was roasted. 

Experiment No. 87 was made with fresh ham from a Duroc-Jersey hog about 8 
months old, fed on peas, oats, and barley. One portion (1543) was uncooked and the 
other portion (1558) was roasted. 

Experiment No. 88 was made with fresh ham from a Yorkshire hog about 8 months 
old, fed on peas, oats, and barley. One portion (1544) was uncooked and the other 
portion (1559) was roasted. 

Experiment No. 89 was made with two portions (1573 and 1574; of roasted ham 
from a Duroc-Jersey hog about 8 months old, fed on peas, oats, and barley. 

Experiment No. 90 was made with two portions (1575 and 1580) of roasted ham 
from a Yorkshire hog about 8 months old fed on corn. 

The data of the experiments are given in Table 37. 

Table 37. — Results obtained in artificial digestion of cuts of fresh pork, raw and cooked. 



Labo- 
ra*" 

tory 
No. 



1430 
1431 
1432 
1433 
1434 



Description of sample. 



Digested 1 hour. 

Experiments Nos. 61-65: 

Pork, different cuts, all cooked in 
water 2 hours — 

Belly 

Middle cut 

Ham 

Shoulder 

Pack 



Num- 
lier of 
tests 
in av- 
erage. 



Nitrogen in- 



Meat. 



Gram. 

0. 0578 
.0724 
.0631 
.0759 
.0667 



Undi^ 
gested 
por- 
tion. 



Gram. 

0. 0144 
.0167 
.0084 
.0115 
.0064 



Digest- 
ed por- 
tion. 



Gram. 

0. 0434 
.0557 
.0547 
. 0644 
.0603 



Proportion of total ni- 
trogen in digested 
portion. 



Aver- 


Mini- 


Maxi- 


age. 


mum. 


mum. 


Per ct. 


Per ct. 


Per ct. 


75.09 


73. 88 


75.65 


7f). 93 


76. 78 


77.06 


86.69 


85.97 


87.74 


84. 85 


84.45 


85. 44 


90.40 


90.04 


91.05 



92 

Table 37. — Results obtained in artificial digestion of cuts of fresh pork, raw andcoolced- 

Continued. 



Labo- 
ra- 
tory 
No. 



1430 
1431 
1432 
1433 
1434 

1482 
1483 

1485 
1484 

1487 
1486 

1488 
1489 

1490 
1491 

1492 
1493 

1505 
1504 

1507 
1506 

1510 
1511 

1515 
1514 

1542 
1545 

1543 
1558 

1544 
1559 

1573 
1574 



1575 
1580 



Description of sample. 



1430 
1431 
1432 
•1433 
1434 



Digested Z hours. 

Experiments Nos. 61-65: 

Pork, different cuts, all cooked in 
water 2 lioiirs- 

Belly 

Middle cut 

Ham 

Shoulder 

Back 

Experiment No. 71: 

Fresh ham, raw 

Fresh ham, roasted ,. . . 

Experiment No. 72: 

Fresh ham, raw 

Fresh ham, roasted 

Experiment No. 73: 

Fresh ham, raw 

Fresh ham, roasted 

Experiment No. 74: 

Fresh ham, raw 

Fresh ham. roasted 

Experiment No. 75: 

Fresh ham, raw 

Fresh ham, roasted 

E.xperiment No. 76: 

Fresh ham, raw 

Fresh ham, roasted 

Experiment No. 77: 

Fresh ham, raw '. ... 

Fresh ham, roasted 

Experiment No. 78: 

Fresh ham, raw 

Fresh ham. roasted 

Experiment No. 70: 

Fresh ham, raw 

Fresh ham, roasted 

Experiment No. 80: 

Fresh ham, raw 

Fresh ham, roasted 

Experiment No. 86: 

Fresh ham, raw 

Fresh ham, roasted 

Experiment No. 87: 

Fresh ham, raw 

Fresh ham, roasted 

Experiment No. 88: 

Fresh ham, raw 

Fresh ham, roasted 

Experiment No. 89: 

Fresh ham, raw 

Fresh ham, roasted 



Experiment No. 90: 

Fresh ham, roasted. 
Do 



Average of 2 

Digested 4 hours. 



Num- 
ber of 
tests 
in av- 
erage. 



Experiments Nos. 61-65: 
Pork, dilTcrent cuts, 
water 2 hours — 

Belly 

Middle cut 

Ham 

Shoulder 

Back 



all cooked in 



Nitrogen in — 



Meat. 



Gram. 

0. 0624 
.0538 
.0722 

.0674 
. 0606 

.0422 
.0896 

.0488 
.0579 

. 0599 
. 0885 

.0690 
.0605 

.0686 
. 0869 

.0707 
. 0559 

.0628 
.0676 

.0661 
.0763 

. 0677 
.0743 

. 0753 
.0736 

. 0643 
.0618 

. 0669 
.0745 

.0792 
. 0605 

.0781 
.0763 



Undi- 
gested 
(Por- 
tion. 



.0910 
. 0:125 



.0768 



.0590 
.0549 
.0618 
.0685 
.0633 



Gram. 

0.0102 
.0084 
.0071 
.0072 
.0037 

.0043 
.0129 

. 0057 
.0085 

.0047 
.0108 

. 0058 
. OOC.O 

\0044 
. 0204 

.0113 
.0128 

.0094 
. 0069 

.0073 
. 0065 

.0085 
. 0055 

.0110 
.0060 

.0083 
.0087 

.0092 
. 0157 

.0074 
.0080 

.0080 
.0073 



Digest- 
ed por- 
tion. 



. 0102 
.0095 



.0099 



. 0067 
.0059 
.0035 
.0039 
.0029 



Gram. 

0. 0522 
.0454 
.0651 
.0602 
.0569 

.0379 
.0767 

. 0431 
.0495 

. 0552 
.0777 

. 0632 
.0545 

.0642 
.0665 

.0594 
.0431 

.0534 
.0607 

. 0588 
.0698 

.0592 
.0688 

.0643 
.0676 

. 0560 
.0531 

. 0577 
.0588 

.0718 
. 0525 

.0701 
.0690 



. 0530 



.0669 



. 0523 
.0490 
.0583 
.0646 
.0604 



Proportion of total ni- 
trogen in digested 
portion. 



Aver- 
age. 



Per ct. 

83. 65 
84.39 
90.17 
89.32 
93.89 

89.81 
85.60 

88.32 
85.49 

92.15 

87.80 

91.59 
90.08 

93.59 
76.52 

84.02 
77.10 

85.03 
89.79 

88. 96 
91.48 

87.44 
92.60 

85.39 
91. 85 

87.09 
85.92 

86.25 
78.92 

90.66 
86.78 

89.76 
90.43 



Mini- 
mum. 



88.79 
84.80 



86.80 



88. 64 
89.25 
94.34 
94.31 
95.42 



Per ct. 

82. 90 
83.97 
89.23 
87.85 
92.83 

89. 05 
84.50 

87.08 
85.01 

91.84 
87.62 

91.30 
89.06 

92.03 

75. 17 

83. 05 
76.50 

84.41 

88. 91 

88.59 
90.24 

87.24 
92.21 

82.05 
91.80 

86.46 
83.70 

85. 09 
78. 73 

89.94 
85.10 

87.01 
90.03 



Maxi- 
mum. 



88.53 
84.36 



88.26 
88.11 
93.88 
93.93 
95.14 



Per ct. 
84.67 
84.91 
91.51 
91.11 
95. 18 

90. 26 
86.58 

89.71 
85.58 

92.29 
88.09 

91.72 
90.66 

94.89 

78.91 

85.24 
77.94 

85.94 
90.77 

89.61 
92.34 

87.79 
92.82 

88.18 
91.89 

87.40 

88.79 

87.64 
79. 16 

91.61 
88.53 

91.04 
90.88 



88. 98 
85.44 



88.81 
90.07 
94.82 
94.58 
95.51 



93 

Table 37. — Results obtained in artificial digestion of cuts of fresh pork, raw and cooked- 
Continued. 



Labo- 
ra- 
tory 
No. 






Description of sampln. 



Digested 6 hours. 

Experiments Nos. 61-65: 

Pork, different cuts, all cooked in 
water 2 hours — 

1430 Bellv 

1431 ■ Middle cut 

1432 "^ Ham 

1433 Shoulder 

1434 Back '. 

Digested 24 hours. 

Experiments Nos. 61-65: 

Pork, different cuts, all cooked in 
water 2 hours— 

1430 Belly 

1431 ! Middle cut 

1432 I Ham 

1433 Shoulder 

1434 j Back 

Experiment No. 71: 

1482 I Fresh ham, raw 

1483 Fresh ham, roasted 

Experiment No. 72: 

1485 Fresh ham, raw 

1484 1 Fresh ham, roasted 

Experiment No. 73: 

1487 I Fresh ham, raw 

1486 ■ Fresh ham, roasted 

Experiment No. 74: 

1488 ! Fresh ham, raw 

1489 Fresh ham, roasted 

I Experiment No. 75: 

1490 Fresh ham, raw 

1491 Fresh ham, roasted 

Experiment No. 76: 

1492 I Fresh ham, raw 

1493 I Fresh ham, roasted 

Experiment No. 77: 

1505 j Fresh ha:n, raw 

1504 I Fresh ham. roasted 

Experiment No. 78: 
1507 j Fresh ham, raw 

1506 I Fresh ham, roasted 

Experiment No. 79: 

1510 I Fresh ham, raw 

1511 ; Fresh ham, roasted 

Experiment No. 80: 

1515 I Fresh ham, raw : . . . 

1514 I Fresh ham, roasted 

i Experiment No. 86: 

1542 I Fresh ham, raw 

1545 ', Fresh ham, roasted 

j Experiment No. 87: 

1543 ' Fresh ham, raw 

1558 Fresh ham, roasted 

' Experiment No. 88: 

1544 ' Fresh ham, raw 

1559 j Fresh ham, roasted 

I Experiment No. 89: 

1573 ! Fresh ham, raw 

1574 Fjesh ham, roasted 

; Experiment No. 90: 



Num- 
ber of 
tests 
in av- 
erage. 



1575 
1580 



Fresh ham, roasted. 
Do 



Average of 2 . 



Nitrogen in- 



Proportion of total ni- 
trogen in digested 
portion. 



Undi- 
Meat. I %l^ 
tion. 



Gram. 

3 0. 0626 

4 . 0674 
3 . 0591 
3 .0673 
2 .0653 



.0721 
.0644 
.0721 
.0626 
.0850 

.0566 



.0475 
.0541 

.0669 
.0697 

.0556 
.0650 

.0753 
.0808 

.0701 
.0573 

.0709 
.0523 

.0702 
.0660 

.0657 
.0707 

.0759 
.0801 

.0831 
.0664 

.0791 
.0827 

.0773 
.0621 

.0720 
.0747 



Gram. 

0. 0043 
. 0045 
.0026 
.0030 
.0029 



.0827 
.0524 



.0676 



.0022 
.0022 
.0021 
.0016 
.0022 

.0022 
.0040 

.0014 
.0023 

.0026 
.0031 

.0020 
.0026 

.0024 
.0041 

.0028 
.0027 

.0028 
.0023 

.0024 
.0026 

.0021 
.0028 

.0029 
.0032 

.0050 
.0018 

.0060. 
.0034 

.0028 
.0025 

.0023 
.0029 



?^fnr'' Aver- 



Gram. 

0.0583 
.0629 
.0565 
.0643 
.0624 



.0699 
.0622 
.0700 
.0610 
.0828 

.0544 
.0768 

.0461 
.0518 

.0643 
.0666 

.0536 
.0624 

.0729 

.0767 

.0673 
.0546 

.0681 
.0500 

.0678 
.0634 

.0636 
.0679 

.0730 
.0769 

.0781 
.0646 

.0731 
.0793 

; 0745 
.0596 

.0697 
.0718 



Mini- 
mum. 



.0030 
.0030 



.0197 
.0494 



.0030 



.0646 



Per ct. 
93.13 
93.32 
95.60 
95.54 
95.56 



96.95 
96.58 
97.09 
97.44 
97.41 

96.11 
95.05 

97.05 
95.75 

96.11 
95. 55 

96.40 
96.00 

96.81 
94.93 

96.01 
95.29 

96.05 
95.60 

96.51 
96.06 

96.80 
96.04 

96.18 
96.00 

93.98 
97.29 

92.41 
95.89 

96.38 
95.96 

96.81 
96.12 



Per ct. 
92.37 
92. a3 
95.45 
95.17 
95.26 



96.37 
94.27 



95.32 



Maxi- 
mum. 



95.82 
96.42 
96.78 
97.12 
97.30 

95.67 
94.59 

96.79 
95.59 

95.72 
95.19 

96.19 
95.49 

%.64 
94.64 

95.85 
94.39 

95.82 
95.18 

96.45 
95.05 

96.53 
95.73 

96.13 
95.43 

91.69 
97.29 

91.32 
95. 38 

95.16 
95.68 

96.64 
95.45 



Per ct. 
93.92 
94.44 
95.81 
95.82 
95.90 



98.44 
96.88 
97.39 
97.65 
97.64 

96.66 
95.50 

97.32 
95.99 

96.49 
95.76 

%.66 
%.41 

97.02 
95.22 

96.06 
96.60 

96.26 
95.98 

96.57 
96.08 

97.26 
96.53 

96.33 
96.34 

95.96 
97.29 

94.11 
96.32 

97.42 
96.17 

96.90 
96.44 



96.29 
93.53 



96.57 
95.10 



94 



SUMMARY AND DISCUSSION OF RESULTS. 

For convenience in discussion, the data of Tables 35 to 37 that are 
of especial significance are here summarized so as to show the different 
kinds and cuts of meat used, the different methods of cooking, the 
lengths of the digestive periods, and the average coefficients of 
digestibility of protein obtained. 

Table 38. — Summary of results of artificial digestion experiments with beef. 



Lab- 
ora- 
tory 
No. 


Kind of meat and method of cooking. 


Proportion of total protein digested 
digestion was continued for— 


when 


1 hour. 


2 hours. 


4 hours. 


6 hours. 


24 hours. 


1202 


Beef round: 

Raw 


Per cent. 

92 

o51 

a 62 

75 

73 

86 
84 
88 
78 
75 

89 

84 
82 
84 
78 

89 
81 
85 
76 
83 

83 
72 
77 
77 
86 

88 
80 

84 
79 

84 
88 


Per cent. 
94 
73 
75 

82 
87 

91 
92 
91 

87 
82 

91 
92 
90 
90 
91 

89 
86 
92 
88 
90 

84 
84 
84 
79 
92 

92 

88 

88 
82 

90 
90 


Per cent. 
94 
85 
87 
91 
92 

94 
94 
95 
93 

89 

90 
95 
94 
96 
95 

94 
90 
95 
91 
89 

89 
88 
90 
86 
92 

94 
91 

94 
90 

93 
94 


Per cent. 
95 
89 
93 
95 
95 

95 
97 
94 
95 
90 

95 
96 
96 
97 
96 

96 
95 
96 
93 
94 

92 
95 
94 
88 
93 

95 
93 

95 
92 

95 
95 


Per cent. 
97 


1205 


Cooked in water 2 hours 


95 


1206 


Cooked iu water 5 hours 


96 


1203 


Pan broiled 


96 


1204 


Fried in hot lard 


96 


1210 


Raw 


97 


1211 


Cooked in water 2 hours 


97 


1212 


Cooked in water 5 hours 


95 


1215 


Pan broiled 


95 


1219 


Fried in hot lard 


94 


1235 


Raw. . 


96 


1242 


Cooked in water 1 hour 


97 


1243 


Cooked in water 5 hours . . 


97 


1238 


Pan broiled 


97 


1241 


Fried in hot lard 


98 


1388 


Raw 


98 


1390 


Cooked in water 2 hours 


96 


1389 


Pan broiled 1 


98 


1391 


Fried in hot lard 


97 


1392 


Roasted * 


97 


1393 


Raw 


97 


1395 


Cooked in water 2 hours 


97 


1394 


Pan broiled 


97 


1396 


Fried in hot lard 


96 


1397 


Roasted 


97 


1314 


Raw 


97 


1313 




97 


1331 


Raw 


97 


1330 


Fried in hot lard 


96 


1348 


Raw 


96 


1347 


Roasted 


95 




Average of above S series of experi- 
ments: 
Raw 






87 
84 
82 
85 
80 
76 
85 


90 
92 
84 
91 
87 
85 
90 


^ 93 
95 
89 
92 
93 
90 
92 


95 
96 
94 
94 
95 
92 
94 


97 




Cooked in water 1 hour 

Cooked in water 5 hours 

Pan broiled 


97 
96 
96 
97 




Fried in hot lard 


96 




Roasted 

Beef round : 

Cooked in water 2 hours, ground twice 
in a sausage mill 


97 


1634 


1 


82 
24 




94 
39 


97 


1635 


Cooked in water 2 hours, cut into quar- 
ter-inch cubes 






89 




Beef sirloin: 

Raw 








1302 


79 
80 
82 


88 
87 
88 


93 
93 
95 


95 
94 

98 


99 


1303 


Do 


99 


1305 


Do 


95 




Average of 3 






80 


88 


93 


96 


98 









a Not included in the average. 



95 



Table 38. — Summary of results of artificial digestion experiments with beef — Continued. 



Lab- 
ora- 


Kind of meat and method of cooking. 


Proportion of total proteki digested when 
digestion was continued for — 


tory 
No. 


1 hour. 


2 hours. 


4 hours. 


6 hours. 


24 hours. 


1306 


Beef sirloin: 

B roiled 


Percrnt. 
80 
80 
83 


Percent. 
87 
86 
86 


Percent. 
90 
92 
91 


Percent. 
93 
93 
93 


Per cent. 
96 


1307 


Do 


96 


1309 


Do 


98 




\vera2fp of 3 






81 


87 


91 


93 


97 




Beef sirloin: 

Broiled 




1279 


84 
76 
74 

81 
77 


86 
85 
80 
87 
82 


94 
91 
83 
93 
91 


94 
94 
90 
95 
93 




1280 


Do 




1281 


Do 




1282 


Do 




1283 


Do 






A ver;^ so of 5 






78 


84 


90 


93 






Beef shoulder: 

Very fat, cooked in water 2 hours 




1287 
1300 


79 
84 


85 
86 


91" 
91 


91 
93 


97 
97 












86 
85 
81 




95 




Beef ribs, roasted, average of 8 experiments. 
Beef ribs, roasted, average of 9 experiments. 

Beef, different cuts, all cooked in water 2 
hours : 
First cut, rilis 






95 






94 






1 




1399 


78 
07 
75 
67 
80 


87 
78 
79 
73 
89 


89 
85 

88 
85 
92 


91 
90 
92 

87 
93 


96 


1400 


Leg bone . 


96 


1401 


Second cut, neck 


93 


1402 


Flank 


93 


1403 


Round 


93 




Average 






73 


81 


88 


91 


94 




hours : 
First cut, rilas 




1461 


78 
78 
70 
68 
83 






90 
93 
89 
86 
95 


95 


1462 


Leg bone 


85 
74 
74 

88 


91 
86 
82 
93 


97 


1463 




95 


1464 


Flank 


96 


1465 


Round 

Average 


97 




76 


80 


88 


90 


96 




Mutton, different cuts, all cooked in water 
at 80° to 8o° C. for 2 hours: 
Shoulder 




1424 


82 
70 
85 
76 
80 


86 
82 
89 
83 
84 


88 
84 
93 
89 
91 


93 
87 
95 
90 
91 


95 


1425 


Flank 


94 


1426 


Leg .... 


98 


1427 


Loin 


96 


1428 


Ribs. . 


96 




Average 






79 


84 


89 


91 


96 




Pork, different cuts, all cooked in water at 
80° to 85° C. for 2 hours: 
Belly 




1430 


75 

77 
87 
85 
90 


84 
84 
90 
89 
94 


89 
89 
94 
94 
95 


93 
93 
96 
96 
96 


97 


1431 


Middle cut 


97 


1432 


Ham 


97 


1433 


Shoulder 


97 


1434 


Back 


97 




Average 






83 


,88 


92 


95 


97 




Ham, raw, average of 14 experiments 








89 

86 

87 






96 




Ham, roasted, average of 14 experiments 








96 




Ham, roasted, average of 2 tests 








95 













The figures in Table 38 show what proportions of the total nitrogen 

contained in the meat that was treated with the artificial digestive 

solution were present in the material that was dissolved when the 

action was allowed to continue for the lengths of time specified in the 

4663— Bull. 193—07 7 



96 

column lieatlings. For convenience in discussing results the data 
may be considered as representing the proportions of protein digested 
under the given conditions. 

It "svill be observed that at the end of the 24-hour periods about 97 
per cent of the protein was digested and the results were practically 
uniform for the different samples. At the end of the 6-hour period the 
proportion was about 94 per cent, and at four hours 92 per cent, and 
the variations in the results for the different samples in either of these 
periods are for the most part not especially large. The proportion of 
protein digested in the 2-hour period was near 90 per cent and in the 
1-hour period it was generally over 80 per cent, but in these periods 
there were considerable variations in the results for different samples. 
TMiatever information is to be derived from the results resrarding the 
relative ease of digestion of the meats cooked in different ways should 
be supplied by the data for these later periods. 

The several series of experiments with lean beef round afford excel- 
lent opportunity for comparison. One fact that is especially notice- 
able is the lack of uniformity in the results for different samples of 
meat digested under uniform conditions. For example, samples 
Nos. 1388 to 1392 were different portions of t}ie same cut of beef round 
from one animal, and samples Xos. 1393 to 1397 were corresponding 
portions of a cut from another animal. With the former sample 89 
per cent of the protein of the raw meat was digested in one hour and but 
83 per cent of that of the roasted meat, whereas with the latter sample 
the coefficient for the raw meat was only 83 per cent and that for the 
roasted meat was 86 per cent. With the former sample the coeffi- 
cient for meat cooked in water two hours was 81 per cent and with 
the latter only 72 per cent. Since the experimental conditions were as 
nearly identical as they could be made in the various series of tests, 
it would seem as if the fact that the two sets of samples were from 
different animals offers some explanation of the variations, though 
the coefficients for meat fried in hot lard were practically identical in 
both cases — 76 and 77 per cent. 

Averaging the results obtained in the eight series with meat from 
different animals tends to ec[ualize the variations observed. The coef- 
ficients for raw meat range from 83 to 92 per cent, and the mean of 
these — 87 per cent — is the same as the average of the eight tests. 
There was but one test with meat cooked one hour in water, and in this 
the coefficient was 84 per cent. With meat cooked two hours in water 
one test gave only 51 per cent of the protein digested, but this test 
was not entirely satisfactor}* and the result is not included in the 
average. In the other test a coefficient of 72 per cent was obtained, 
but in two tests the figures were 81 and 84 per cent, the average of 
the two being 82 per cent. In one test with meat cooked five hours 
in water the coefficient was 61 per cent, but this test was also not 



97 

entirely satisfactory. In the two other tests the figures were 82 afid 
88 per cent, averaging 85 per cent. The results of the six tests with 
pan broiled meat ranged from 75 to 85 per cent, averaging 80 per 
cent, and those for the six tests with meat fried in hot lard ranged 
from 73 to 79 per cent and averaged 76 per cent. It is noticeable 
that the meat thus cooked was in each experiment less digestible in 
one hour than that cooked in other ways. The average of the three 
tests with roasted meat is 85 per cent. 

In general it may be said that the differences in the average results 
for raw meat and meat cooked in various ways are, on the whole, too 
small to be of much significance; and, especially in view of the varia- 
bleness in the results of individual tests, it seems fair to assume that 
so far as can be judged from these experiments there is no practical 
difference — at least not a constant one — in the ease of digestion of 
meat cooked in different ways. The only exception is that of fried 
meat; in this case, in each indi^ddual test, as well as in the average, the 
effect of the action of the digestive solution for one hour was less than 
in the case of any of the other samples, which would seem to indi- 
cate that the fried meat is perhaps not so easily digested as meat 
otherwise cooked. 

In these eight series of tests the coefficient for raw meat was in 
several individual cases somewhat larger than those for the cooked 
meats, and it is also slightly larger in the average. This might sug- 
gest that the raw meat was more easily digested — that is, that cooking 
the meat will tend to decrease the ease of digestion. One fact, how- 
ever, should be considered — all of the cooked meats had probably lost 
in cooking more or less of the water-soluble nitrogenous material 
that was not removed from the raw meat before digestion, and which 
would consequently be dissolved and form part of the digested mate- 
rial, and thus make the apparent digestibility of the raw meat rather 
larger than the actual. If allowance were made for this, the results 
for the raw meat, at least in the average, might perhaps be no larger 
than those for the cooked meat. 

The experiments with samples Nos. 1634 and 1635 were planned to 
give some idea of the effect of more or less thorough mastication upon 
the ease of digestion. Each sample was from the same piece of beef 
round, cooked in water two hours. Sample No. 1634 was ground 
twice in a sausage mill to represent meat somewhat thoroughly mas- 
ticated, whereas sample No. 1635 was cut into small pieces, about a 
quarter-inch cube, to represent meat less thoroughly masticated. 
Both samples were digested two, six, and twenty-four hours. The 
results obtained were several times larger with the ground meat than 
with that in cubes in both the two and six hour periods, and even 
with twenty-four hours' digestion the result with the more coarsely 



98 

ground meat was decidedh^ the smaller. The inference is that thor- 
ough chewing may have a very decided influence upon the ease of 
digestion of meat proteid. 

The results of three individual tests with raw beef sirloin agree very 
closely with each other in both the one and the two hour periods, and 
so do the results with the three corresponding tests with broiled beef 
sirloin; and the average of the tests with the raw beef are practically 
identical with the average of the results for the cooked meat in the cor- 
responding tests. In live other tests with broiled sirloin, however, 
rather wide variations were found in the results for the different sam- 
ples in the same period; 

In eight experiments beef ribs raw and roasted ^\:ere compared. In 
each case the meat for roasting was one portion and the meat not 
cooked was another portion of the same cut. With these samples 
digestion was carried on for only the 2 and 24 hour periods. In the 
results for the 24-hour period there was practical uniformity for all the 
samples, the variation being noticeable in the case of only one sample. 
In the 2-hour period the digestibility of the raw meat ranged from 82 
to 91 per cent and that of the roasted meat fsom 81 to 97 per cent. In 
one experiment the coefficient for raw meat was 91 per cent and that 
for roasted meat 97 per cent, whereas in another experiment the coeffi- 
cient for raw meat was 90 per cent and that for roasted 82 per cent, 
but the average of all the tests with raw meat — 86 per cent — is prac- 
tically identical with that for the tests with roasted meat — 85 per cent. 
In nine other tests with roasted meat the range is from 73 to 88 per 
cent and the average 81 per cent. 

In one experiment five different cuts of beef from the same animal 
were used and in another experiment the same cuts from another ani- 
mal. In four cases the results with a given cut from one animal were 
not much different from those for the same cut from the other animal, 
but in the case of the leg cut the difference was quite appreciable. 

In the series of tests with different cuts of mutton from the same 
animal the difference between the maximum and minimum results in 
the one-hour period was quite wide, but in the results for digestion for 
two hours the coefficients agree fairly well with each other, the differ- 
ences being of little i:)ractical significance. In experiments with five 
cuts of pork from the same animal, all cooked in the same manner, 
three of the cuts — ham, shoulder, and back — agree fairly well with 
each other in the one-hour digestion period, but the results with the 
other two cuts were somewhat lower than with these. In the 2-hour 
period the differences are slightly smaller. 

There were fourteen experiments in which raw fresh ham was com- 
pared with roasted fresh ham when digestion had been carried on two 
and twenty-four hours. In each case the samples in the two tests 
were from the same piece of meat. In nine tests the coefficients in the 



99 

2-hour period were larger for the raw than for the roasted ham, and in 
five tests the reverse was true. The hirgest coefficient for the raw ham, 
94 per cent, and the smallest for the roasted ham, 77 per cent, were 
found in the same experiment. The average for all the samples of raw 
ham is but little larger than that for the roasted ham. 

A comparison of the relative ease of digestion of the difi"erent kinds 
of meat — beef, mutton, and pork — is interesting. This can be made 
by averaging the results of those experiments in which different cuts 
of the same animal were used, since in each case the method of cook- 
ing the meat was the same. In all five periods the average figures for 
pork are the highest, those for mutton next, and those for beef last, 
though the difference between the beef and the mutton is smaller in 
the longer than in the shorter periods of digestion. On the other hand, 
the average of raw fresh ham in the 2-hour period is 89 per cent, that 
of raw beef ribs 86 per cent, and of raw beef round 90 per cent ; and 
that of roasted fresh ham is 86 per cent, of roasted beef ribs 85 per 
cent, and of roasted beef round 90 per cent. 

CONCLUSIONS. 

In twenty-three natural digestion experiments with men the same 
kind of meat — beef round — cooked in various ways, was eaten w4th 
several other common food materials in a rather varied diet. The 
average digestibility of the nutrients of the total diet was as follows: 
Protein, 93 per cent; fat, 98 per cent, and carbohydrates, 97 per cent. 
These coefficients agree very closely with those found in the average 
of several hundred digestion experiments with varied diet. 

In these experiments differences in method of cooking the meat 
had no appreciable effect upon the proportions of nutrients digested 
and absorbed from the total diet. 

In forty-four experiments different kinds of meat — beef, veal, 
mutton, and pork — cooked in various ways, were eaten wdth two or 
three other common food materials in a very simple diet, and the 
digestibility of the meat alone was deterinined. In the average of 
the results of these experiments the digestibility of the protein was 
98 per cent and of the fat 98 per cent. 

Differences in the results obtained with different kinds of meat or 
with the same kind of meat cooked in different ways were too small 
to be of any practical significance. 

The relative fatness of the meat had no appreciable effect upon the 
thoroughness of digestion, the nutrients of very fat meat being 
digested as completely as those of very lean meat, including that from 
which in some cases part of the visible fat had been removed before 
cooking. 

In short, all the kinds and cuts of meat were very thoroughly 
digested, whatever the method of cooking. 



100 

The above-mentioned coefficients of digestibility of the nutrients 
of meat are those derived according to the usual method from the 
quantity of each in the food and the total quantity in the corre- 
sponding feces. When allowance was made for the metabolic prod- 
ucts in the feces, the results obtained indicated that the nutrients of 
the meat were completely digestible. 

It is commonly said tliat meats of different sorts vary decidedly 
in digestibility; for instance, that red meat is less digestible than 
white meat or beef" than pork, or that a cheap cut is less digestible 
than a tender steak. As regards the thoroughness of digestion the 
results of the extended series of tests reported show that such differ- 
ences do not exist in any appreciable degree, and that meat of all 
kinds and cuts is to be classed with the very digestible foods. 

Ninety-nine artificial digestion experiments made for the purpose 
of testing the relative ease of digestion of different kinds and cuts 
of meat cooked in different ways do not w^arrant any sweeping deduc- 
tions. So far as can be judged from the results obtained under the 
experimental conditions the meat seems to be quite easily digested. 
About 80 per cent of the meat protein was digested in the first hour 
and nearly 90 per cent within two hours, Vhatever the kind of meat 
or the method of cooking, though there were considerable variations 
from these proportions in the individual experiments. The differ- 
ences with the several kinds of meat or with meat cooked in a variety 
of ways are very small or very irregular, and in some cases are ap- 
parently contradictory, so it can not be said that they indicate any 
difference that could be attributed to the factors mentioned. 

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